Automatic tuning apparatus for a video tape recorder

ABSTRACT

An automatic tuning apparatus capable of automatically switching the tuning mode of a tuner circuit, automatically arranging various signal data in or after completion of tuning and arbitrarily and automatically arranging various signal data by the user comprises a SYNC discrimination circuit (11) discriminating whether a video signal system is the NTSC system or another system, a tuning mode switching circuit (12) for switching the tuning mode, and a color discrimination circuit (13) receiving a color bust signal (identical signal) for discriminating whether the video signal system is the PAL system or the SECAM system. As to the NTSC system, the PAL system, the SECAM system and the SECAM-L system, the user may not set the tuning mode of tuning means, whereby an automatic tuning apparatus imposing no burden on the user can be obtained.

This application is a Division of application Ser. No. 08/581,422 filedon Dec. 29, 1995, U.S. Pat. No. 5,959,700.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an automatic tuning apparatus, and moreparticularly, it relates to an automatic tuning apparatus for a VTR,which is adapted to discriminate the signal system and process storedsignal information in automatic tuning.

2. Description of the Background Art

A conventional automatic tuning apparatus for a VTR (video taperecorder) is now described with reference to FIGS. 51 to 53. FIG. 51 isa block diagram showing a principal part in the conventional automatictuning apparatus for a VTR, and FIG. 52 is a flow chart as to itsoperation. FIG. 53 shows the relations between station numbers(expedient broadcasting station numbers) and position numbers (expedientnumbers on the VTR unit for selecting the broadcasting stations) aftercompletion of tuning.

Referring to FIG. 51, numeral 2 denotes a tuner circuit which can beswitched in correspondence to a video signal system by an externalcontrol signal, numeral 3 denotes a video signal processing circuit(referred to as Y/C in the figure) including a synchronizing signal(abbreviated as SYNC) separation circuit which receives a compositevideo signal S1 from the tuner circuit 2 and carries out signalprocessing, numeral 4 denotes an AFT detection circuit which detectspresence/absence of a broadcasting station by a signal received from thetuner circuit 2, numeral 5 denotes a tuning control circuit, and numeral6 denotes a memory circuit, and a system controller 7 is formed by thetuning control circuit 5 and the memory circuit 6. Numeral 8 denotes aninput signal system switch for switching the operation of the tuningcontrol circuit 5 in response to the carrier system of the input signal.

The operation is now described with reference to FIGS. 52 and 53. First,the operation of automatic tuning (hereinafter referred to as autotuning) is described with reference to the flow chart of FIG. 52. When acommand for automatic tuning (hereinafter referred to as auto tuning) isreceived from the user, the system controller 7 sets the tuning mode ofthe tuner circuit 2 at the PAL system and sets a memory address of thememory 6 at a station number "0", as initialization (step ST1).

Then, a tuning control signal S3 is transmitted to the tuner circuit 2,to control the same in a direction for increasing its tuning frequencyby a constant amount (step ST2).

At this time, an AFT (automatic fine tuning) signal S4 which isoutputted from the AFT detection circuit 4 and a SYNC signal S2indicating presence/absence of a signal separated by the video signalprocessing circuit 3 are inputted in the tuning control 5 for making adiscrimination, in order to detect presence/absence of a broadcastingstation transmitting a signal of the frequency (step ST3).

When both of the AFT signal S4 and the SYNC signal S3 are supplied atthis point of time, the tuning control circuit 5 determines that it hasbeen possible to receive the signal from the broadcasting station, andstores current tuning data in the address of the station number "0" inthe memory 6 (step ST4). The tuning data indicates data related to thefrequency.

Then, the address of the memory 6 is incremented by one to a stationnumber "1" to enter a next tuning operation, in order to store nexttuning data (step ST5).

When both of the AFT signal S4 and the SYNC siual S2 are not supplied,on the other hand, a discrimination is made as to whether or not thecurrent frequency reaches the upper limit of the tuning frequency, i.e.,whether or not the tuning is ended (step ST6). The tuning is ended ifthe current frequency reaches the upper limit of the tuning frequency,otherwise the operation at the step ST2 is carried out again. Theoperations at the steps ST2 to ST6 are repeated, so that the tuning isended when the frequency reaches the upper limit of the tuningfrequency.

The tuning data obtained by the tuning is supplied to a channelselection system from the address in the memory 6, so that a positionnumber for channel selection is allotted and the tuning mode is ended.

Results obtained by the aforementioned auto tuning are expressed asshown in FIG. 53. FIG. 53 shows station numbers of the addresses of thememory 6 and the tuning data stored therein, and the relations betweenthe station numbers and the position numbers for channel selection.

FIG. 53 indicates that frequency data corresponding to transmissionfrequencies of "B station", "D station", "C station" and "A station" arestored in the station numbers "0" to "3" as the tuning datarespectively. On the other hand, it indicates that no data to be storedare present, i.e., no broadcasting stations are present in the stationnumbers "4" to "99".

In the channel selection system, the frequency data corresponding to thetransmission frequencies of "B station", "D station", "C station" and "Astation" are stored in the position numbers "0" to "3" respectively,while the position numbers "4" to "99" are skipped since no data readingis necessary.

The user can use the channel selection system of the VTR from the pointof time when the auto tuning is completed, and obtain a tuned signal byselecting a switch corresponding to the position number. In the autotuning, the tuning operation is carried out only as to a signal which istransmitted in the PAL system, and hence no signal transmitted in atransmission system other than the PAL system can be obtained. In orderto tune a signal of a transmission system other than the PAL system, theinput signal system switch 8 which is connected to the tuning controlcircuit 5 is so switched that the tuning control circuit 5 supplies acontrol signal SCON for switching the input signal system to the tunercircuit 2.

The conventional automatic tuning apparatus is structured in theaforementioned manner, and hence the transmission system of the inputsignal is set at the PAL system in initialization. In order to tune asignal of a transmission system other than the PAL system, the user mustmanually switch the input signal system switch 8 after completion ofauto tuning, to carry out re-tuning.

In the auto tuning, further, only the data related to the frequency isstored and hence there are no data as to the type of the tunedbroadcasting station, strongness/weakness of the signal, and the soundand video signal systems which are varied with countries. Thus, the useris disadvantageously forced to select the position in relation to thesedifferences after completion of the auto tuning.

SUMMARY OF THE INVENTION

According to a first aspect of the present invention, an automatictuning apparatus comprises tuner means tune-selecting a prescribedchannel from broadcast electric waves including at least a video signal,video signal processing means receiving the video signal which isoutputted from the tuner means and separating a synchronizing signalwhich is included in the video signal, AFT detection means detectingpresence/absence of a broadcasting station by a signal received from thetuner means tuning control means receiving the synchronizing signal fromthe video signal processing means and an AFT signal from the AFTdetection means for controlling a tuning operation of the tuner means,and memory means which is connected to the tuning control means forstoring data related to at least the tuning frequency of the tunermeans, the automatic tuning apparatus comprises a text data decoderreceiving the video signal which is outputted from the tuner means fordecoding text data included in the video signal, and the tuning controlmeans controls the tuner means by the decoded text data while separatingbroadcasting station information specifying the broadcasting stationfrom the decoded text data for storing the same in the memory meansalong with the data related to the tuning frequency.

According to a second aspect of the present invention, an automatictuning apparatus comprises tuner means tune-selecting a prescribedchannel from broadcast electric waves including at least a video signal,video signal processing means receiving the video signal which isoutputted from the tuner means and separating a synchronizing signalwhich is included in the video signal, AFT detection means detectingpresence/absence of a broadcasting station by a signal received from thetuner means, tuning control means receiving the synchronizing signalfrom the video signal processing means and an AFT signal from the AFTdetection means for controlling a tuning operation of the tuner means,and memory means which is connected to the tuning control means forstoring data related to at least the tuning frequency of the tunermeans, the automatic tuning apparatus comprises noise detection meansreceiving the video signal which is outputted from the tuner means fordetecting a random noise included in the video signal and outputting thesame as noise data, and the noise data is stored in the memory meansalong with the data related to the tuning frequency through the tuningcontrol means.

According to a third aspect of the present invention, an automatictuning apparatus comprises tuner means tune-selecting a prescribedchannel from broadcast electric waves including at least a video signal,video signal processing means receiving the video signal which isoutputted from the tuner means and separating a synchronizing signalwhich is included in the video signal, AFT detection means detectingpresence/absence of a broadcasting station by a signal received from thetuner means, tuning control means receiving the synchronizing signalfrom the video signal processing means and an AFT signal from the AFTdetection means for controlling a tuning operation of the tuner means,and memory means which is connected to the tuning control means forstoring data related to at least the tuning frequency of the tunermeans, the automatic tuning apparatus comprises signal definitiondetection means receiving the video signal which is outputted from thetuner means for detecting signal definition of the video signal andoutputting signal definition data, and the signal definition data isstored in the memory means along with the data related to the tuningfrequency through the tuning control means.

According to a fourth aspect of the present invention, the automatictuning apparatus further comprises character generator means which isconnected to a side of the video signal processing means outputting thevideo signal for superposing the broadcasting station information whichis stored in the memory means on the video signal.

According to a fifth aspect of the present invention, an automatictuning apparatus comprises tuner means tune-selecting a prescribedchannel from broadcast electric waves including at least a video signal,video signal processing means receiving the video signal which isoutputted from the tuner means and separating a synchronizing signalwhich is included in the video signal, AFT detection means detectingpresence/absence of a broadcasting station by a signal received from thetuner means, tuning control means receiving the synchronizing signalfrom the video signal processing means and an AFT signal from the AFTdetection means for controlling a tuning operation of the tuner means,and memory means which is connected to the tuning control means forstoring data related to at least the tuning frequency of the tunermeans, the automatic tuning apparatus comprises synchronizing signaldiscrimination means receiving the synchronizing signal from the videosignal processing means and counting the pulse number of thesynchronizing signal per second for discriminating the video signalsystem of the video signal in response to the pulse number andoutputting the result of the discrimination as a synchronizing signaldiscrimination signal, and tuning mode switching means receiving thesynchronizing signal discrimination signal for outputting a tuning modeswitching signal for changing the tuning mode of the tuner means inresponse to the signal system of the video signal and supplying thesynchronizing signal discrimination signal to the tuning control means,and the tuning mode of the tuner means is automatically changed inresponse to the signal system of the video signal, while the tuning modeof the tuner means is stored in the memory means along with the datarelated to the tuning frequency through the tuning control means.

According to a sixth aspect of the present invention, an automatictuning apparatus comprises tuner means tune-selecting a prescribedchannel from broadcast electric waves including at least a video signal,video signal processing means receiving the video signal which isoutputted from the tuner means and separating a synchronizing signalwhich is included in the video signal, AFT detection means detectingpresence/absence of a broadcasting station by a signal received from thetuner means, tuning control means receiving the synchronizing signalfrom the video signal processing means and an AFT signal from the AFTdetection means for controlling a tuning operation of the tuner means,and memory means which is connected to the tuning control means forstoring data related to at least the tuning frequency of the tunermeans, the automatic tuning apparatus comprises color signaldiscrimination means receiving the synchronizing signal from the videosignal processing means and counting the frequency of a color burstsignal which is superposed on the trailing edge of the synchronizingsignal for discriminating the video signal system of the video signal inresponse to the frequency and outputting the result of thediscrimination as a color signal discrimination signal, and tuning modeswitching means receiving the color discrimination signal for outputtinga tuning mode switching signal for switching the tuning mode of thetuner means in response to the signal system of the video signal andsupplying the color signal discrimination signal to the tuning controlmeans, and the tuning mode of the tuner means is automatically changedin response to the signal system of the video signal, while the tuningmode of the tuner means is stored in the memory means along with thedata related to the tuning frequency through the tuning control means.

According to a seventh aspect of the present invention, an automatictuning apparatus comprises tuner means tune-selecting a prescribedchannel from broadcast electric waves including at least a video signal,video signal processing means receiving the video signal which isoutputted from the tuner means and separating a synchronizing signalwhich is included in the video signal, AFT detection means detectingpresence/.absence of a broadcasting station by a signal received fromthe tuner means, tuning control means receiving the synchronizing signalfrom the video signal processing means and an AFT signal from the AFTdetection means for controlling a tuning operation of the tuner means,and memory means which is connected to the tuning control means forstoring data related to at least the tuning frequency of the tunermeans, the automatic tuning apparatus comprises synchronizing signaldiscrimination means receiving the synchronizing signal from the videosignal processing means and counting the pulse number of thesynchronizing signal per second for discriminating the video signalsystem of the video signal in response to the pulse number andoutputting the result of the discrimination as a synchronizing signaldiscrimination signal, and color signal discrimination means receivingthe synchronizing signal from the video signal processing means andcounting the frequency of a color burst signal which is superposed onthe trailing edge of the synchronizing signal for discriminating thevideo signal system of the video signal in response to the frequency andoutputting the result of the discrimination as a color signaldiscrimination signal, tuning mode switching means receiving thesynchronizing signal discrimination signal and the color signaldiscrimination signal outputting a tuning mode switching signal forswitching the tuning mode of the tuner means in response to the signalsystem of the video signal and supplying the synchronizing signaldiscrimination signal and the color signal discrimination signal to thetuning control means, and the tuning mode of the tuner means isautomatically changed in response to the signal system of the videosignal, while the tuning mode of the tuner means is stored in the memorymeans along with the data related to the tuning frequency through thetuning control means.

According to an eighth aspect of the present invention, an automatictuning apparatus comprises tuner means tune-selecting a prescribedchannel from broadcast electric waves including a video signal and asound signal, sound signal processing means receiving the sound signalwhich is outputted from the tuner means and carrying out sounddemodulation in response to the signal system of the sound signal foroutputting the same as a demodulated sound signal, AFT detection meansdetecting presence/absence of a broadcasting station by a signalreceived from the tuner means, tuning control means receiving thedemodulated sound signal and an AFT signal from the AFT detection meansfor controlling a tuning operation of the tuner means, and memory meanswhich is connected to the tuning control means for storing data relatedto at least the tuning frequency of the tuner means, the soundprocessing means includes a plurality of sound demodulation means whichare supplied with the sound signal in parallel with each other, andvoltage control oscillation means which is connected to each of theplurality of sound demodulation means for oscillating only one differentfrequency among frequencies corresponding to the signal system of thesound signal, while only that of the sound demodulation means having thevoltage control oscillation means oscillating the frequencycorresponding to the sound signal carries out sound demodulation, andthe value of the frequency corresponding to the sound signal is storedin the memory means along with the data related to the tuning frequencythrough the tuning control means.

According to a ninth aspect of the present invention, an automatictuning apparatus comprises tuner means tune-selecting a prescribedchannel from broadcast electric waves including a video signal and asound signal, sound signal processing means receiving the sound signalwhich is outputted from the tuner means and carrying out sounddemodulation in response to the signal system of the sound signal foroutputting the same as a demodulated sound signal. AFT detection meansdetecting presence/absence of a broadcasting station by a signalreceived from the tuner means, tuning control means receiving thedemodulated sound signal and an AFT signal from the AFT detection meansfor controlling a tuning operation of the tuner means, and memory meanswhich is connected to the tuning control means for storing data relatedto at least the tuning frequency of the tuner means, the soundprocessing means includes sound demodulation means, voltage controloscillation means which is connected to the sound demodulation means andoscillating various frequencies corresponding to the signal system ofthe sound signal, and sound detection means which is connected to anoutput side of the sound demodulation means, discriminating whether ornot the sound demodulation means outputs the demodulated sound signal,and supplying the result to the tuning control means, sound demodulationis carried out while making the voltage control oscillation meansoscillate a frequency corresponding to the sound signal, and the valueof the frequency corresponding to the sound signal is stored in thememory means along with the data related to the tuning frequency throughthe tuning control means.

According to a tenth aspect of the present invention, an automatictuning apparatus comprises tuner means tune-selecting a prescribedchannel from broadcast electric waves including at least a video signal,video signal processing means receiving the video signal which isoutputted from the tuner means and separating a synchronizing signalwhich is included in the video signal, AFT detection means detectingpresence/absence of a broadcasting station by a signal received from thetuner means, tuning control means receiving the synchronizing signalfrom the signal processing means and an AFT signal from the AFTdetection means for controlling a tuning operation of the tuner means,and memory means which is connected to the tuning control means forstoring data related to at least the tuning frequency of the tunermeans, the automatic tuning apparatus comprises a text data decoderreceiving the video signal which is outputted from the tuner means fordecoding text data included in the video signal, and sorting controlmeans automatically sorting storage contents which are stored in thememory means, including at least the data related to the tuningfrequency of the tuning means, in previously set order, and the tuningcontrol means controls the tuner means by the decoded text data whileseparating broadcasting station information specifying the broadcastingstation from the decoded text data for storing the same in the memorymeans along with the data related to the tuning frequency, and datarelated to the broadcasting station information and the correspondingtuning frequency are automatically sorted in previously set order.

According to an eleventh aspect of the present invention, an automatictuning apparatus comprises tuner means tune-selecting a prescribedchannel from broadcast electric waves including at least a video signal,video signal processing means receiving the video signal which isoutputted from the tuner means and separating a synchronizing signalwhich is included in the video signal, AFT detection means detectingpresence/absence of a broadcasting station by a signal received from thetuner means, tuning control means receiving the synchronizing signalfrom the video signal processing means and an AFT signal from the AFTdetection means for controlling a tuning operation of the tuner means,and memory means which is connected to the tuning control means forstoring data related to at least the tuning frequency of the tunermeans, the automatic tuning apparatus comprises video signal systemdiscrimination means receiving the synchronizing signal from the videosignal processing means for discriminating the video signal system ofthe video signal and supplying the result of the discrimination to thetuning control means as video signal system information, and sortingcontrol means automatically sorting storage contents which are stored inthe memory means, including at least the data related to the tuningfrequency of the tuning means, in previously set order, the video signalsystem information is stored in the memory means along with the datarelated to the tuning frequency through the tuning control means, anddata related to the video signal system information and thecorresponding tuning frequency are automatically sorted in previouslyset order.

According to a twelfth aspect of the present invention, the video signalsystem discrimination means includes synchronizing signal discriminationmeans receiving the synchronizing signal from the video signalprocessing means and counting the pulse number of the synchronizingsignal per second for discriminating the video signal system of thevideo signal in response to the pulse number, and the video signalsystem information is a synchronizing signal discrimination signal whichis outputted from the synchronizing signal discrimination means as theresult of the discrimination.

According to a thirteenth aspect of the present invention, the videosignal system discrimination means includes color signal discriminationmeans receiving the synchronizing signal from the video signalprocessing means and counting the frequency of a color burst signalwhich is superposed on the trailing edge of the synchronizing signal fordiscriminating the video signal system of the video signal in responseto the frequency, and the video signal system information is a colorsignal discrimination signal which is outputted from the color signaldiscrimination means as the result of the discrimination.

According to a fourteenth aspect of the present invention, the videosignal system discrimination means includes synchronizing signaldiscrimination means receiving the synchronizing signal from the videosignal processing means and counting the pulse number of thesynchronizing signal per second for discriminating the video signalsystem of the video signal in response to the pulse number, and colorsignal discrimination means receiving the synchronizing signal from thevideo signal processing means and counting the frequency of a colorburst signal which is superposed on the trailing edge of thesynchronizing signal for discriminating the video signal system of thevideo signal in response to the frequency, and the video signal systeminformation is a synchronizing signal discrimination means and a colorsignal discrimination signal which is outputted from the synchronizingsignal discrimination means and the color signal discrimination means asthe results of the discriminations.

According to a fifteenth aspect of the present invention, an automatictuning apparatus comprises tuner means tune-selecting a prescribedchannel from broadcast electric waves including a sound signal and avideo signal, video signal processing means receiving the video signalwhich is outputted from the tuner means and separating a synchronizingsignal which is included in the video signal, AFT detection meansdetecting presence/absence of a broadcasting station by a signalreceived from the tuner means, tuning control means receiving thesynchronizing signal from the video signal processing means and an AFTsignal from the AFT detection means for controlling a tuning operationof the tuner means, and memory means which is connected to the tuningcontrol means for storing data related to at least the tuning frequencyof the tuner means, and the automatic tuning apparatus comprises soundsignal system discrimination means receiving the sound signal which isoutputted from the tuner means for discriminating the signal system ofthe sound signal and supplying the result of the discrimination to thetuning control means as sound signal system information, and sortingcontrol means automatically sorting storage contents which are stored inthe memory means, including at least the data related to the tuningfrequency of the tuning means, in previously set order, while the soundsignal system information is stored in the memory means alone with thedata related to the tuning frequency through the tuning control means,and data related to the sound signal system information and thecorresponding tuning frequency are automatically sorted in previouslyset order.

According to a sixteenth aspect of the present invention, the soundsignal system discrimination means includes a plurality of sounddemodulation means which are supplied with the sound signal in parallelwith each other, and voltage control oscillation means which isconnected to each of the plurality of sound demodulation means foroscillating only one different frequency among frequencies correspondingto the signal system of the sound signal, and the sound signal systeminformation is the value of the frequency of the voltage controloscillation means oscillating the frequency corresponding to the soundsignal.

According to a seventeenth aspect of the present invention, the soundsignal system discrimination means included sound demodulation means,voltage control oscillation means which is connected to the sounddemodulation means and oscillating various frequencies corresponding tothe signal system of the sound signal, and sound detection means whichis connected to an output side of the sound demodulation means,determining whether or not the sound demodulation means outputs thedemodulated sound signal, and supplying the result to the tuning controlmeans, and the sound signal system information is the value of thefrequency which is oscillated by the voltage control oscillation meansfor demodulating the sound signal in the sound demodulation means.

According to an eighteenth aspect of the present invention, theautomatic tuning apparatus further comprises sorting order set meanswhich is connected to the memory means for arbitrarily setting sortingorder of the storage contents.

According to a nineteenth aspect of the present invention, an automatictuning apparatus comprises tuner means tune-selecting a prescribedchannel from broadcast electric waves including at least a video signal,video signal processing means receiving the video signal which isoutputted from the tuner means and separating a synchronizing signalwhich is included in the video signal, AFT detection means detectingpresence/absence of a broadcasting station by a signal received from thetuner means, tuning control means receiving the synchronizing signalfrom the video signal processing means and an AFT signal from the AFTdetection means for controlling a tuning operation of the tuner means,and memory means which is connected to the tuning control means forstoring data related to at least the tuning frequency of the tunermeans, the automatic tuning apparatus comprises picture definitiondiscrimination means receiving the video signal which is outputted fromthe tuner means for discriminating the degree of picture definition ofthe video signal and supplying the result of the discrimination to thetuning control means as picture definition information, and sortingcontrol means automatically sorting storage contents which are stored inthe memory means, including at least data related to the tuningfrequency of the tuning means, in previously set order, the picturedefinition information is stored in the memory means along with the datarelated to the tuning frequency through the tuning control means, anddata related to the picture definition information and the correspondingtuning frequency are automatically sorted in order of the degree ofpicture definition.

According to a twentieth aspect of the present invention, the picturedefinition discrimination means has picture definition detection meansreceiving the video signal which is outputted from the tuning means anddetecting signal definition of the video signal, and the picturedefinition information is a picture definition signal which is outputtedfrom the picture definition detection means as the result of thediscrimination.

In the automatic tuning apparatus according to the first aspect of thepresent invention, the broadcasting station information specifying thebroadcasting station is separated from the decoded text data in thetuning control means and stored in the memory means along with the datarelated to the tuning frequency, whereby the broadcasting stationinformation can be recognized at need during and after completion ofautomatic tuning.

In the automatic tuning apparatus according to the second aspect of thepresent invention, the noise data is stored in the memory means alongwith the data related to the tuning frequency, whereby the broadcastelectric wave receiving situation can be recognized at need during andafter completion of automatic tuning.

In the automatic tuning apparatus according to the third aspect of thepresent invention, the receiving situation of broadcast electric wavesincluding not only a simple noise but jamming and ghost waves can berecognized at need during and after completion of automatic tuning.

In the automatic tuning apparatus according to the fourth aspect of thepresent invention, the broadcasting station information can be displayedon a receiver screen due to provision of the character generator meansfor superposing the broadcasting station information stored in thememory means on the video signal.

In the automatic tuning apparatus according to the fifth aspect of thepresent invention, the tuning mode of the tuner means is automaticallychanged in response to the signal system of the video signal which isdiscriminated by the synchronizing signal discrimination means and thistuning mode of the tuner means is stored in the memory means along withthe data related to the tuning frequency through the tuning controlmeans, whereby the user may not set the tuning mode of the tuner meansas to the signal system of the video signal which is discriminated bythe synchronizing signal discrimination means, i.e., as to the PALsystem or the NTSC system.

In the automatic tuning apparatus according to the sixth aspect of thepresent invention, the tuning mode of the tuner means is automaticallychanged in response to the signal system of the video signal which isdiscriminated by the color signal discrimination means and this tuningmode of the tuner means is stored in the memory means along with thedata related to the tuning frequency through the tuning control means,whereby the user may not set the tuning mode of the tuner means as tothe signal system of the video signal which is discriminated by thecolor signal discrimination means, i.e., as to the PAL system, the SECAMsystem or the SECAM-L system.

In the automatic tuning apparatus according to the seventh aspect of thepresent invention, the tuning mode of the tuner means is automaticallychanged in response to the signal system of the video signal which isdiscriminated by the synchronizing signal discrimination means and thecolor signal discrimination means and this tuning mode of the tunermeans is stored in the memory means along with the data related to thetuning frequency through the tuning control means, whereby the user maynot set the tuning mode of the tuner means as to the signal system ofthe video signal which is discriminated by the synchronizing signaldiscrimination means and the color signal discrimination means, i.e., asto the NTC system, the PAL system, the SECAM system or the SECAM-Lsystem.

In the automatic tuning apparatus according to the eighth aspect of thepresent invention, the sound demodulation means having the voltagecontrol oscillation means oscillating the frequency corresponding to thesound signal carries out sound demodulation among those provided inparallel with each other, whereby the time required for the sounddemodulation is short and the broadcast electric waves can bediscriminated by the signal system of the sound signal during and aftercompletion of automatic tuning, and the discrimination of the soundsignal can be quickened and classification of the broadcast electricwaves can be further refined, and an automatic tuning apparatus suitablefor employment in an area having various broadcast electric waves in amixed state can obtained.

In the automatic tuning apparatus according to the ninth aspect of thepresent invention, the voltage control oscillation means is made tooscillate the frequency corresponding to the sound signal for carryingout sound demodulation, whereby the numbers of necessary sounddemodulation means and voltage control oscillation means can be reducedand the broadcast electric waves can be discriminated by the signalsystem of the sound signal during and after completion of automatictuning, and the discrimination of the sound signal can be quickened andclassification of the broadcast electric waves can be further refined,and an automatic tuning apparatus suitable for employment in an areahaving various broadcast electric waves in a mixed state can beobtained.

In the automatic tuning apparatus according to the tenth aspect of thepresent invention, the broadcasting station information specifying thebroadcasting station is separated from the decoded text data in thetuning control means and stored in the memory means along with the datarelated to the tuning frequency while the broadcasting stationinformation and the data related to the corresponding tuning frequencyare automatically sorted in previously set order, whereby the user maynot set a call number in correspondence to the broadcasting stationinformation.

In the automatic tuning apparatus according to the eleventh aspect ofthe present invention, the video signal system information is stored inthe memory means along with the data related to the tuning frequencythrough the tuning control means while the video signal systeminformation and the data related to the corresponding tuning frequencyare automatically sorted in previously set order, whereby the user maynot set a call number in correspondence to the video signal systeminformation.

In the automatic tuning apparatus according to the twelfth aspect of thepresent invention, the video signal system discrimination means has thesynchronizing signal discrimination means so that the video signalsystem information is formed by the synchronizing signal discriminationsignal which is outputted as the result of the discrimination, wherebythe user may not set a call number in correspondence to the video signalsystem information as to the signal system of the video signal which isdiscriminated by the synchronizing signal discrimination means.

In the automatic tuning apparatus according to the thirteenth aspect ofthe present invention, the video signal system discrimination means hasthe color signal discrimination means so that the video signal systeminformation is formed by the color signal discrimination signal which isoutputted as the result of the discrimination, whereby the user may notset a call number in correspondence to the video signal systeminformation as to the signal system of the video signal which isdiscriminated by the color signal discrimination means, i.e., as to thePAL system, the SECAM system or the SECAM-L system.

In the automatic tuning apparatus according to the fourteenth aspect ofthe present invention, the video signal system discrimination means hasthe synchronizing signal discrimination means and the color signaldiscrimination means so that the video signal system information isformed by the synchronizing signal discrimination signal and the colorsignal discrimination signal, whereby the user may not set a call numberin correspondence to the video signal system information as to thesignal system of the video signal which is discriminated by thesynchronizing signal discrimination means and the color signaldiscrimination means, i.e., as to the NTSC system, the PAL system, theSECAM system or the SECAM-L system.

In the automatic tuning apparatus according to the fifteenth aspect ofthe present invention, the sound signal system information is stored inthe memory means along with the data related to the tuning frequencythrough the tuning control means and the sound signal system informationand the data related to the corresponding tuning frequency areautomatically sorted in previously set order, whereby the user may notset a call number in correspondence to the sound signal systeminformation.

In the automatic tuning apparatus according to the sixteenth aspect ofthe present invention, the sound signal system discrimination means hasa plurality of sound demodulation means which are supplied with thesound signal in parallel with each other and the voltage controloscillation means which is connected to each of the plurality of sounddemodulation means for oscillating only one different frequency amongthose corresponding to the signal system of the sound signal so that thesound signal system information is formed by the value of the frequencyof the voltage control oscillation means oscillating the frequencycorresponding to the sound signal, whereby the time required fordiscriminating the sound signal system is short. Hence thediscrimination of the sound signal is quickened and no operation forsetting the call number is required, whereby an automatic tuningapparatus imposing onto burden on the user can be obtained.

In the automatic tuning apparatus according to the seventeenth aspect ofthe present invention, the sound signal system discrimination means hasthe sound demodulation means, the voltage control oscillation meanswhich is connected with the sound demodulation means and oscillatingvarious frequencies corresponding to the signal system of the soundsignal, and the sound detection means which is connected to the outputside of the sound demodulation means for discriminating whether or notthe demodulated sound signal is outputted from the sound demodulationmeans and supplying the result to the tuning control means, and thesound signal system information is formed by the value of the frequencyoscillated by the voltage control oscillation means in order todemodulate the sound signal in the sound demodulation means, whereby thenumbers of the required sound demodulation means and voltage controloscillation means can be reduced, and no operation for setting the callnumber is required, whereby an automatic tuning apparatus imposing noburden on the user can be obtained.

The automatic tuning apparatus according to the eighteenth aspect of thepresent invention further comprises the sorting order set means which isconnected with the memory means for arbitrarily setting the sortingorder for the storage contents, whereby an automatic tuning apparatushaving a large degree of freedom for the user can be obtained.

In the automatic tuning apparatus according to the nineteenth aspect ofthe present invention, the picture definition information is stored inthe memory means along with the data related to the tuning frequencythrough the tuning control means while the picture definitioninformation and the data related to the corresponding tuning frequencyare sorted in order of degrees of picture definition, whereby the usermay not set the call number in correspondence to the order of degrees ofpicture definition.

In the automatic tuning apparatus according to the twentieth aspect ofthe present invention, the picture definition discrimination means hasthe picture definition detection means receiving the video signaloutputted from the tuner means for detecting the signal definition ofthe video signal so that the picture definition information is formed bythe picture definition signal outputted as the result of thediscrimination, whereby the degrees of picture definition can bediscriminated in relation to not only simple noises but jamming andghost waves.

An object of the present invention is to obtain an automatic tuningapparatus which can automatically switch the tuning mode of a tunercircuit in correspondence to a sound signal system and a video signalsystem, automatically arrange various signal data in correspondence to apreviously set position number during or after completion of tuning, orautomatically arrange various signal data in correspondence to aposition number required by the user.

The foregoing and other objects, features, aspects and advantages of thepresent invention will become more apparent from the following detaileddescription of the present invention when taken in conjunction with theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates the structure of an automatic tuning apparatusaccording to a first embodiment of the present invention;

FIG. 2 illustrates a partial structure of the automatic tuning apparatusaccording to the first embodiment of the present invention;

FIG. 3 is a flow chart for illustrating the operation of the automatictuning apparatus according to the first embodiment of the presentinvention;

FIG. 4 illustrates the structure of an automatic tuning apparatusaccording to a second embodiment of the present invention;

FIG. 5 illustrates a partial structure of the automatic tuning apparatusaccording to the second embodiment of the present invention;

FIG. 6 is a flow chart for illustrating the operation of the automatictuning apparatus according to the second embodiment of the presentinvention;

FIG. 7 illustrates the structure of an automatic tuning apparatusaccording to a third embodiment of the present invention;

FIG. 8 illustrates a partial structure of the automatic tuning apparatusaccording to the third embodiment of the present invention;

FIG. 9 is a flow chart for illustrating the operation of the automatictuning apparatus according to the third embodiment of the presentinvention;

FIG. 10 illustrates the structure of an automatic tuning apparatusaccording to a fourth embodiment of the present invention;

FIG. 11 illustrates an exemplary operation of the automatic tuningapparatus according to the fourth embodiment of the present invention;

FIG. 12 illustrates an exemplary operation of a modification of theautomatic tuning apparatus according to the fourth embodiment of thepresent invention;

FIG. 13 illustrates an exemplary operation of a modification of theautomatic tuning apparatus according to the fourth embodiment of thepresent invention;

FIG. 14 illustrates the structure of an automatic tuning apparatusaccording to a fifth embodiment of the present invention;

FIG. 15 illustrates a partial structure of the automatic tuningapparatus according to the fifth embodiment of the present invention;

FIG. 16 is a flow chart for illustrating the operation of the automatictuning apparatus according to the fifth embodiment of the presentinvention;

FIG. 17 is a flow chart for illustrating the operation of the automatictuning apparatus according to the fifth embodiment of the presentinvention;

FIG. 18 illustrates the structure of an automatic tuning apparatusaccording to a sixth embodiment of the present invention;

FIG. 19 is a flow chart for illustrating the operation of the automatictuning apparatus according to the sixth embodiment of the presentinvention;

FIG. 20 illustrates the structure of an automatic tuning apparatusaccording to a seventh embodiment of the present invention;

FIG. 21 is a flow chart for illustrating the operation of the automatictuning apparatus according to the seventh embodiment of the presentinvention;

FIG. 22 illustrates the structure of an automatic tuning apparatusaccording to an eighth embodiment of the present invention;

FIG. 23 is a flow chart for illustrating the operation of the automatictuning apparatus according to the eighth embodiment of the presentinvention;

FIG. 24 is a flow chart for illustrating the operation of the automatictuning apparatus according to the eighth embodiment of the presentinvention;

FIG. 25 illustrates the structure of an automatic tuning apparatusaccording to a ninth embodiment of the present invention;

FIG. 26 illustrates a partial structure of the automatic tuningapparatus according to the ninth embodiment of the present invention;

FIG. 27 is a flow chart for illustrating the operation of the automatictuning apparatus according to the ninth embodiment of the presentinvention;

FIG. 28 illustrates the structure of an automatic tuning apparatusaccording to a tenth embodiment of the present invention;

FIG. 29 illustrates a partial structure of the automatic tuningapparatus according to the tenth embodiment of the present invention;

FIG. 30 is a flow chart for illustrating the operation of the automatictuning apparatus according to the tenth embodiment of the presentinvention;

FIG. 31 is a flow chart for illustrating the operation of the automatictuning apparatus according to the tenth embodiment of the presentinvention;

FIG. 32 illustrates the structure of an automatic tuning apparatusaccording to an eleventh embodiment of the present invention;

FIG. 33 illustrates a partial structure of the automatic tuningapparatus according to the eleventh embodiment of the present invention;

FIG. 34 is a flow chart for illustrating the operation of the automatictuning apparatus according to the eleventh embodiment of the presentinvention;

FIG. 35 is a flow chart for illustrating the operation of the automatictuning apparatus according to the eleventh embodiment of the presentinvention;

FIG. 36 illustrates the structure of an automatic tuning apparatusaccording to a twelfth embodiment of the present invention;

FIG. 37 is a flow chart for illustrating the operation of the automatictuning apparatus according to the twelfth embodiment of the presentinvention;

FIG. 38 is a flow chart for illustrating the operation of the automatictuning apparatus according to the twelfth embodiment of the presentinvention;

FIG. 39 illustrates a partial structure of an automatic tuning apparatusaccording to a thirteenth embodiment of the present invention;

FIG. 40 is a flow chart for illustrating the operation of the automatictuning apparatus according to the thirteenth embodiment of the presentinvention;

FIG. 41 is a flow chart for illustrating the operation of the automatictuning apparatus according to the thirteenth embodiment of the presentinvention;

FIG. 42 illustrates the structure of an automatic tuning apparatusaccording to a fourteenth embodiment of the present invention;

FIG. 43 is a flow chart for illustrating the operation of the automatictuning apparatus according to the fourteenth embodiment of the presentinvention;

FIG. 44 is a flow chart for illustrating the operation of the automatictuning apparatus according to the fourteenth embodiment of the presentinvention;

FIG. 45 illustrates the structure of an automatic tuning apparatusaccording to a fifteenth embodiment of the present invention;

FIG. 46 is a flow chart for illustrating the operation of the automatictuning apparatus according to the fifteenth embodiment of the presentinvention;

FIG. 47 is a flow chart for illustrating the operation of the automatictuning apparatus according to the fifteenth embodiment of the presentinvention;

FIG. 48 illustrates the structure of an automatic tuning apparatusaccording to a sixteenth embodiment of the present invention;

FIG. 49 is a flow chart for illustrating the operation of the automatictuning apparatus according to the sixteenth embodiment of the presentinvention;

FIG. 50 is a flow chart for illustrating the operation of the automatictuning apparatus according to the sixteenth embodiment of the presentinvention;

FIG. 51 illustrates the structure of a conventional automatic tuningapparatus;

FIG. 52 is a flow chart for illustrating the operation of theconventional automatic tuning apparatus; and

FIG. 53 illustrates the operation of the conventional automatic tuningapparatus.

DESCRIPTION OF THE PREFERRED EMBODIMENTS First Embodiment

FIG. 1 shows the structure of an automatic tuning apparatus A1 for a VTRaccording to a first embodiment of the present invention. Referring toFIG. 1, numeral 2A denotes a tuner circuit which is connected to anantenna 1, numeral 3 denotes a video signal processing circuit includinga SYNC separation circuit receiving a composite video signal S1 from thetuner circuit 2A and carrying out signal processing, numeral 4 denotesan AFT detection circuit receiving a signal from the tuner circuit 2Aand detecting presence/absence of a broadcasting station, numeral 5denotes a tuning control circuit for controlling the tuning operation ofthe tuner circuit 2A, and numeral 6 denotes a memory circuit which isconnected with the tuning control circuit 5, and a system controller 7is formed by the tuning control circuit 5 and the memory circuit 6.Numeral 10 denotes a text data decoder circuit receiving the videosignal S1 and extracting a teletext signal S5, which is information fromthe broadcasting station, from the video signal S1 for supplying thesame to the tuning control circuit 5.

With reference to FIG. 2, the structure of the text data decoder circuit10 is now described. Referring to FIG. 2, the text data decoder circuit10 is formed by a blanking detection circuit 101 and a blanking gatecircuit 102 which are supplied with the video signal S1, and a text datadetection circuit 103 which is connected to the blanking gate circuit102 and outputs the teletext signal S5.

The operation is now described. The blanking detection circuit 101detects a part (vertical blanking period) of the video signal S1 havingno actual signal such as a picture in the vicinity of a synchronizingsignal, and supplies a blanking signal S101 to the blanking gate circuit102. In the video signal S1 which is supplied to the blanking gatecircuit 102, only the part having no actual signal such as the picturein the vicinity of the synchronizing signal is extracted in response tothe blanking signal S101 and supplied to the text data detection circuit103, so that text data included in this part is read in the text datadetection circuit 103 and outputted as the teletext signal S5.

The operation of the automatic tuning apparatus A1 is now described withreference to a flow chart shown in FIG. 3. When a command for autotuning is received from the user, the system controller 7 sets thetuning mode of the tuner circuit 2A at the PAL system while setting thememory address of the memory 6 at a station number "0" as initialization(step ST1).

Then, a tuning control signal S3 is transmitted to the tuner circuit 2A,to control the same in a direction for increasing the tuning frequencyby a constant amount (step ST2). In order to detect presence/absence ofa broadcasting station transmitting a signal of the frequency at thistime, an AFT (automatic fine tuning) signal S4 outputted from the AFTdetection circuit 4 and a SYNC signal S2 indicating presence/absence ofa signal separated by the video signal processing circuit 3 are inputtedin the tuning control circuit 5, for making a discrimination (step ST3).

If both of the AFT signal S4 and the SYNC signal S2 are supplied at thispoint of time, the tuning control circuit 5 determines that the signalfrom the broadcasting station can be received, and stores the currenttuning data (data related to the frequency) in the address of thestation number "0" in the memory 6 (step ST4).

At the same time, the text data decoder circuit 10 decodes textinformation which is superposed on a blanking period of the signal fromthe composite video signal S1, so that the decoded teletext signal S5 isinputted in the tuning control circuit 5 (step ST5).

The tuning control circuit 5 extracts broadcasting station informationfrom the teletext signal S5, and stores the same in the address of thestation number "0" in the memory 6, similarly to the data related to thefrequency (step ST6).

Then, the address of the memory 6 is incremented by one to a stationnumber "1" in order to store next tuning data, and the process advancesto a next tuning operation (step ST7).

If both of the AFT signal S4 and the SYNC signal S2 are not supplied atthe step ST3, on the other hand, a discrimination is made as to whetheror not the current frequency reaches the upper limit of the tuningfrequency, i.e., whether or not the tuning is ended (step ST8). Thetuning is ended if the current frequency reaches the upper limit of thetuning frequency, otherwise the operation at the step ST2 is carried outagain so that the operations through the steps ST2 to ST7 are repeated,and the tuning is ended when the frequency reaches the upper limit ofthe tuning frequency.

The tuning data obtained by the tuning is supplied to a system forchannel selection from the address of the memory 6, so that a positionnumber for channel selection is allotted thereto and the tuning mode isended.

The automatic tuning apparatus A1 for a VTR according to the presentinvention comprises the text data decoder circuit 10 and the memory 6 ofthe system controller 7 stores the broadcasting station informationalong with data related to the frequency, whereby the broadcastingstation can be discriminated through the teletext signal S5 serving asbroadcasting station information during and after completion of the autotuning operation.

While the broadcasting station information is extracted from theteletext signal S5 in the tuning control circuit 5 in the aforementionedautomatic tuning apparatus A1, the broadcasting station information maybe replaced by another information, or all of the teletext signal may beextracted and stored. For example, an error rate of text data may becalculated to discriminate the state of a received electric field.

While the data related to the frequency and the teletext signal arestored only in the auto tuning operation in the aforementioned automatictuning apparatus A1, a teletext signal of a currently received videosignal may be stored in the system controller 7 after completion of autotuning, so that the same is compared with that in the auto tuning or thedata is updated. Thus, it is possible to cope with such case that thereceived electric field or the broadcasting station is changed after theauto tuning.

While the aforementioned automatic tuning apparatus A1 determinespresence/absence of the broadcasting station in the auto tuningoperation by inputting both of the AFT signal S4 and the SYNC signal S2in the system controller 7, the same may alternatively be determinedonly through presence/absence of the teletext signal S5, the AFT signalS4 or the SYNC signal S2, for example.

If any broadcasting station has no teletext signal S5, this fact can bestored in the system controller 7.

While the frequency is increased from the lower side to the higher sidein the auto tuning operation of the aforementioned automatic tuningapparatus A1, the frequency may alternatively be reduced from the higherside to the lower side. When there are various frequency bands for VHF,UHF and the like, the tuning may be carried out from any frequency bandor only in a specific frequency band. Further, the tuning direction maybe varied with the frequency band.

The tuning control signal S3 which is outputted from the tuning controlcircuit 5 is a dc voltage, a PWM pulse, or serial data.

Second Embodiment

FIG. 4 illustrates the structure of an automatic tuning apparatus A2 fora VTR according to a second embodiment of the present invention.Referring to FIG. 4, a noise detection circuit 20 for detecting thenoise quantity of a received signal and outputting the same as noisedata S6 is provided in place of the text data decoder circuit 10 of theautomatic tuning apparatus A1 according to the first embodiment shown inFIG. 1. The structural parts of this embodiment which are identical tothose of the automatic tuning apparatus A1 shown in FIG. 1 are denotedby the same reference numerals, to omit redundant description.

With reference to FIG. 5, the structure of the noise detection circuit20 is now described. Referring to FIG. 5, the noise detection circuit 20is formed by an inversion delay circuit 201 for inverting and delaying avideo signal S1, and a noise amplification circuit 202 receiving thevideo signal S1 and an inverted delay signal S201 of the video signal S1and amplifying the noise. The inversion delay circuit 201 is provided inparallel with the line of the video signal, and inverts the same whilesupplying a delay (64 μs) for one horizontal scanning period(hereinafter abbreviated as 1H), and supplying the same to the videosignal S1.

The video signal S1, which has correlation every 1H, itself disappearsto leave only a random noise when the inverted delay signal S201 issupplied. This random noise is amplified by the noise amplificationcircuit 202, thereby obtaining noise data S6.

With reference to a flow chart shown in FIG. 6, the operation of theautomatic tuning apparatus A2 is now described. When a command for autotuning is received from the user, a system controller 7 sets the tuningmode of a tuner circuit 2A at the PAL system, and sets the memoryaddress of a memory 6 at a station number "0" as initialization (stepST1).

Then, a tuning control signal S3 is transmitted to the tuner circuit 2A,to control the same in a direction for increasing the tuning frequencyby a constant amount (step ST2).

In order to detect presence/absence of a broadcasting stationtransmitting a signal of the frequency at this time, an AFT signal S4outputted from an AFT detection circuit 4 and a SYNC signal S2indicating presence/absence of a signal separated by a video signalprocessing circuit 3 are inputted in a tuning control circuit 5, formaking a discrimination (step ST3).

If both of the AFT signal S4 and the SYNC signal S2 are supplied at thispoint of time, the tuning control circuit 5 determines that the signalfrom the broadcasting station can be received, and stores the currenttuning data (data related to the frequency) in the address of thestation number "0" in the memory 6 (step ST4).

At the same time, the noise data S6 which is outputted from the noisedetection circuit 20 is inputted in the tuning control circuit 5 (stepST5).

In the tuning control circuit 5, the noise data S6 is stored in theaddress of the station number "0" in the memory 6, similarly to the datarelated to the frequency (step ST6).

Then, the address of the memory 6 is incremented by one to a stationnumber "1" in order to store next tuning data, and the process advancesto a next tuning operation (step ST7).

If both of the AFT signal S4 and the SYNC signal S2 are not supplied atthe step ST3, on the other hand, a discrimination is made as to whetheror not the current frequency reaches the upper limit of the tuningfrequency, i.e., whether or not the tuning is ended (step ST8). Thetuning is ended if the current frequency reaches the upper limit of thetuning frequency, otherwise the operation at the step ST2 is carried outagain so that the operations through the steps ST2 to ST7 are repeated,and the tuning is ended when the frequency reaches the upper limit ofthe tuning frequency.

The tuning data obtained by the tuning is supplied to a system forchannel selection from the address of the memory 6, so that a positionnumber for channel selection is allotted thereto and the tuning mode isended.

The automatic tuning apparatus A2 for a VTR according to the presentinvention comprises the noise detection circuit 20 and the memory 6 ofthe system controller 7 also stores the noise data S6 as information ofthe receiving situation along with the data related to the frequency,whereby the receiving situation of the receiving station can berecognized during and after completion of the auto tuning operation, toallow comparison with other receiving stations and discrimination of thereceiving electric field.

While the noise detection circuit 20 comprises the noise amplifier 202for amplifying a general noise of an amplification direction fordetecting the noise quantity with respect to the composite video signalS1 in the aforementioned automatic tuning apparatus A2, the noiseamplifier 202 may be replaced by means for detecting the noise level ofa sound signal, means for detecting the noise level of a video signal ora sound signal before demodulation, or means for detecting the level ofRF-AGC (automatic gain control for making sensitivity of a tuner systemconstant) which is varied with the receiving electric field, oralternatively by means for detecting an edge of the SYNC signal S2 andcalculating its S-N ratio or means for detecting only a verticalsynchronizing signal and detecting its S-N ratio.

While the data related to the frequency and the noise data are storedonly in an auto tuning operation in the aforementioned automatic tuningapparatus A2, noise data of a currently received video signal may bestored in the system controller 7 after completion of the auto tuningfor carrying out comparison with the data in the auto tuning or updatingthe data. Thus, it is possible to cope with change of the receivingelectric field or the broadcasting station caused after the auto tuning.

While the frequency is increased from the lower side to the higher sidein the auto tuning operation of the aforementioned automatic tuningapparatus A2, the frequency may alternatively be reduced from the higherside to the lower side. When there are various frequency bands for VHF,UHF and the like, the tuning may be carried out from any frequency bandor only in a specific frequency band. Further, the tuning direction maybe varied with the frequency band.

The tuning control signal S3 which is outputted from the tuning controlcircuit 5 is a dc voltage, a PWM pulse, or serial data.

Third Embodiment

FIG. 7 illustrates the structure of an automatic tuning apparatus AB fora VTR according to a third embodiment of the present invention.Referring to FIG. 7, a picture definition detection circuit 30 isprovided in place of the text data decoder circuit 10 of the automatictuning apparatus A1 according to the first embodiment shown in FIG. 1.The structural parts of this embodiment which are identical to those ofthe automatic tuning apparatus A1 shown in FIG. 1 are denoted by thesame reference numerals, to omit redundant description.

The structure of the picture definition detection circuit 30 is nowdescribed. FIG. 8 is a block diagram showing the structure of thepicture definition detection circuit 30. Referring to FIG. 8, numeral301 denotes a blanking detection circuit for detecting a blanking partin a video signal St, which is outputted from a tuner circuit 2A, havingno actual signal, numeral 302 denotes a blanking gate circuit forpassing the blanking part with respect to the video signal S1 inresponse to a blanking signal S301 which is detected by the blankingdetection circuit 301, and numeral 303 denotes a noise detection circuitfor detecting a noise component of only the blanking part. The noisedetection circuit 303 outputs picture definition data S7 which isproportional to the noise quantity of the blanking part of the videosignal S1 having no actual signal.

The operation is now described. First, the blanking detection circuit301 detects the blanking part of the obtained video signal S1, andoutputs the blanking signal S301 in correspondence to this part.Further, the blanking gate circuit 302 which opens/closes its gate inresponse to the blanking signal S301 for passing only the blanking partextracts only the blanking part from the video signal S1, so that thenoise detection circuit 303 carries out noise detection of only theblanking part. Thus, picture definition data S7 of the received signalis formed by the noise detection output of only the blanking part of thevideo signal S1, whereby presence/absence of a jam signal etc, can alsobe detected in addition to simple noise detection, determination ofghost etc, is enabled, and definition of the received signal can becorrectly discriminated.

With reference to a flow chart shown in FIG. 9, the operation of theautomatic tuning apparatus A3 is now described. When a command for autotuning is received from the user, a system controller 7 sets the tuningmode of a tuner circuit 2A at the PAL system, and sets the memoryaddress of a memory 6 at a station number "0" as initialization (stepST1).

Then, a tuning control signal S3 is transmitted to the tuner circuit 2A,to control the same in a direction for increasing the tuning frequencyby a constant amount (step ST2). In order to detect presence/absence ofa broadcasting station transmitting a signal of the frequency at thistime, an AFT signal S4 which is outputted from an AFT detection circuit4 and a SYNC signal S2 indicating presence/absence of a signal separatedby a video signal processing circuit 3 are inputted in a tuning controlcircuit 5, for making a discrimination (step ST3).

If both of the AFT signal S4 and the SYNC signal S2 are supplied at thispoint of time, the tuning control circuit 5 determines that the signalfrom the broadcasting station can be received, and stores the currenttuning data (data related to the frequency) in the address of thestation number "0" in the memory 6 (step ST4).

At the same time, the picture definition detection circuit 30 detectsthe picture definition of the currently received composite video signalS1, outputs the same as picture definition data S7, and supplies thesame to the tuning control circuit 5 (step ST5).

This picture definition data S7 is stored in the address of the stationnumber "0" in the memory 6, similarly to the data related to thefrequency (step ST6).

Then, the address of the memory 6 is incremented by one to a stationnumber "1" in order to store next tuning data, and the process advancesto a next tuning operation (step ST7).

If both of the AFT signal S4 and the SEYNC signal S2 are not supplied atthe step ST3, on the other hand, a discrimination is made as to whetheror not the current frequency reaches the upper limit of the tuningfrequency, i.e., whether or not the tuning is ended (step ST8). Thetuning is ended if the current frequency reaches the upper limit of thetuning frequency, otherwise the operation at the step ST2 is carried outagain.

The operations through the ST2 to ST7 are repeated, and the tuning isended when the frequency reaches the upper limit of the tuningfrequency. The tuning data obtained by the tuning is supplied to asystem for channel selection from the address of the memory 6, so that aposition number for channel selection is allotted thereto and the tuningmode is ended.

The automatic tuning apparatus A3 for a VTR according to the presentinvention comprises the picture definition detection circuit 30 and thememory 6 of the system controller 7 also stores the picture definitiondata S7 as information of the receiving situation along with the datarelated to the frequency, whereby the receiving situation of thereceiving station can be recognized during and after completion of theauto tuning operation, to allow comparison with other receiving stationsand the discrimination of the receiving electric field.

While the noise detection circuit 303 detects the noise component ofonly the blanking part of the video signal S1 in the picture definitiondetection circuit 30 in the aforementioned automatic tuning apparatusA3, means for detecting a video intermediate frequency signal(hereinafter referred to as a VIF signal) which is outputted from thetuner circuit, or means for making detection at the level of RF-AGC mayalternatively be employed.

While the data related to the frequency and the picture definition dataare stored only in the auto tuning operation in the aforementionedautomatic tuning apparatus A3, picture definition data of a currentlyreceived video signal may be stored in the system controller 7 aftercompletion of the auto tuning for carrying out comparison with the datain the auto tuning or updating the data. Thus, it is possible to copewith change of the receiving electric field or the broadcasting stationcaused after the auto tuning.

While the frequency is increased from the lower side to the higher sidein the auto tuning operation of the aforementioned automatic tuningapparatus A3, the frequency may alternatively be reduced from the higherside to the lower side. When there are various frequency bands for VHF,UHF and the like, tuning may be carried out from any frequency band oronly in a specific frequency band. Further, the tuning direction may bevaried with the frequency band.

The tuning control signal S3 which is outputted from the tuning controlcircuit 5 is a dc voltage, a PWM pulse, or serial data.

Fourth Embodiment

FIG. 10 illustrates the structure of an automatic tuning apparatus A4for a VTR according to a fourth embodiment of the present invention.Referring to FIG. 10. a character generator circuit (hereinafterreferred to as a CG circuit) 40 for superposing data on a video signalS1 for displaying characters etc, on a screen is connected to a videosignal processing circuit 3, so that an output of the CG circuit 40 issupplied to a video signal output terminal 9. The other structural partsof this embodiment are identical to those of the automatic tuningapparatus A1 shown in FIG. 1, and hence the same are denoted by the samereference numerals, to omit redundant description.

The operation of the automatic tuning apparatus A4 is now described.When a command for auto tuning is received from the user, a tuningoperation similar to that of the automatic tuning apparatus A1 iscarried out along the flow chart shown in FIG. 3, while a teletextsignal S5 is extracted from a received broadcasting station signalthrough a text data decoder circuit 10, so that broadcasting stationinformation is stored in a memory 6 of a system controller 7 with datarelated to the frequency.

When the broadcasting information is read from the memory 6 with thedata related to the frequency again after completion of the auto tuning,the broadcasting information is superposed on a video signal through theCG circuit 40 and displayed on a receiver screen.

The CG circuit 40, which is formed by a ROM, stores characters, symbolsetc. consisting of matrices of prescribed dots. This structure isgenerally well known in the art, and hence redundant description isomitted.

FIG. 11 illustrates exemplary display of broadcasting information on areceiver screen SC. Referring to FIG. 11, the name of the currentlyreceived broadcasting station is displayed as "BBC1" on the receiverscreen SC. Thus, the user can recognize the received broadcastingstation information.

While the broadcasting station information is outputted on the receiverscreen after completion of the auto tuning according to this embodiment,the same may alternatively be displayed in the auto tuning. Further, thesame may not be outputted on the receiver screen, but a fluorescentdisplay tube, a light emitting diode or a liquid crystal display may beprovided on a portion out of the receiver screen, to display thebroadcasting station information.

While the screen display content is the broadcasting station informationin the automatic tuning apparatus A4 shown in FIG. 10 since the teletextsignal S5 is extracted from the broadcasting station signal through thetext data decoder circuit 10, the noise detection circuit 20 fordetecting the noise quantity of the received signal described withreference to the second embodiment, for example, may be provided inplace of the text data decoder circuit 10 so that noise data S6outputted therefrom is stored in the memory 6 along with the datarelated to the frequency, and noise data 106 can be read from the memory6 at need to be displayed on the receiver screen.

FIG. 12 shows exemplary display of noise data on a receiver screen SC.Referring to FIG. 12, the noise level of the received signal is shown onthe receiver screen SC with a numerical value and a graph. Thus, theuser can recognize the noise level of the received signal.

The picture definition detection circuit 30 for detecting the noisequantity of the received signal described with reference to the thirdembodiment, for example, may be provided in place of the text datadecoder circuit 10 so that picture definition data S7 outputtedtherefrom is stored in the memory 6 along with the data related to thefrequency, and the picture definition data S7 can be read from thememory 6 at need to be displayed on the receiver screen.

FIG. 13 shows exemplary display of noise data on a receiver screen SC.Referring to FIG. 13, the picture definition of a received signal isshown on the receiver screen SC with a numerical value and a graph.Thus, the user can recognize the picture definition (clear level) of thevideo signal, to recognize the optimum direction of an indoor/outdoorantenna with reference to the screen display of the picture definitiondata, for example.

Fifth Embodiment

FIG. 14 illustrates the structure of an automatic tuning apparatus A5for a VTR according to a fifth embodiment of the present invention.Referring to FIG. 14. Numeral 2 denotes a tuner circuit which isconnected to an antenna 1 for allowing switching in correspondence to aninput signal system by an external control signal, numeral 3 denotes avideo signal processing circuit including a SYNC separation circuitwhich receives a composite video signal S1 from the tuner circuit 2 forcarrying out signal processing, numeral 4 denotes an AFT detectioncircuit which receives a signal from the tuner circuit 2 for detectingpresence/absence of a broadcasting station, numeral 5 denotes a tuningcontrol circuit which controls a tuning operation of the tuner circuit2, numeral 6 denotes a memory which is connected to the tuning controlcircuit, numeral 11 denotes a SYNC discrimination circuit which receivesa SYNC signal S2 outputted from the video signal processing circuit 3for discriminating whether the video signal system is the NTSC system oranother system through the number of the SYNC signal, and numeral 12denotes a tuning mode switching circuit which receives a mode switchingcircuit first control signal S9 outputted from the SYNC discriminationcircuit 11 and outputs a mode switching signal S11 to the tuner circuit2 for switching the tuning mode. A system controller 7A is formed by thetuning control circuit 5, the memory 6, the SYNC discrimination circuit11 and the tuning mode switching circuit 12. Further. a colordiscrimination circuit 13 is provided for receiving a color burst signal(identical signal) S8, which is one of outputs of the video signalprocessing circuit 3, discriminating whether the video signal system isthe PAL system or the SECAM system, and supplying the result to thetuning mode switching circuit 12 as a mode switching circuit secondcontrol signal S10.

The SYNC discrimination circuit 11 has a structure of counting thenumber (pulse number) of SYNC per second by a microcomputer or the like,and makes a discrimination on the NTSC system when 60 SYNCs are countedin one second (60 Hz), or the SECANM system or the PAL system when 50SYNCs are counted in one second.

The color discrimination circuit 13 is now described. FIG. 15 is a blockdiagram showing the structure of the color discrimination circuit 13.Referring to FIG. 15, the color discrimination circuit 13 comprises aburst gate circuit 131 which passes the color bust signal S8 every 1H, afrequency filter 132 which is connected to the burst gate circuit 131for extracting only a color burst signal (identical signal) S8 having afrequency of 4.43 MHz, a DC conversion circuit 133 which DC-converts thesignal passed through the frequency filter 132, and a comparator 135which compares a DC signal outputted from the DC conversion circuit 133with another DC signal obtained by delaying the output of the DCconversion circuit 133 by 1H through a delay circuit 134.

The operation is now described. The color burst signal (identical signalin the SECAM system) S8 is present behind the SYNC signal S2 in generalin either one of the SECAM system and the PAL system as shown in FIG. 15and its frequency is entirely 4.43 MHz in the case of the PAL system,while signals of 4.25 MHz and 4.41 MHz alternately appear every 1H inthe case of the SECANM system. Therefore, the burst gate circuit 131 andthe frequency filter 132 are employed to extract the frequency of thecolor bust signal S8 per 1H by the filter, convert the same to a DCvalue by the DC conversion circuit 132 and compare the DC level per 1Hby the comparator 135, thereby making a discrimination on the PAL systemif the DC level per 1H is identical or on the SECAM system if the DClevel per 1H is different.

With reference to flow charts shown in FIGS. 16 and 17, the operation ofthe automatic tuning apparatus A5 is now described. When a command forauto tuning is received from the user, a system controller 7 sets thetuning mode of the tuner circuit 2 at a PAL system, and sets the memoryaddress of a memory 6 at a station number "0" as initialization (stepST1).

Then, a tuning control signal S3 is transmitted to the tuner circuit 2,to control the same in a direction for increasing the tuning frequencyby a constant amount (step ST2).

At this time, a discrimination is made as to whether or not the currentfrequency reaches the upper limit of the tuning frequency, i.e., whetheror not the tuning is ended (step ST3), so that the tuning is ended ifthe current frequency reaches the upper limit of the tuning frequency,otherwise an AFT signal S4 which is outputted from an AFT detectioncircuit 4 and a SYNC signal S2 indicating presence/absence of a signalseparated by a video signal processing circuit 3 are inputted in thetuning control circuit 5, in order to detect presence/absence of abroadcasting station transmitting a signal of the frequency (step ST4).

If both of the AFT signal S4 and the SYNC signal S2 are supplied at thistime, the tuning control circuit 5 determines that the signal from thebroadcasting station can be received and executes a next step S5. Ifboth of the AFT signal S4 and the SYNC signal S2 are not supplied, onthe other hand, the tuning frequency is increased by a constant amountat the step ST2.

At a step ST5, the SYNC signal S2 from the video signal processingcircuit 3 is transmitted to the SYNC discrimination circuit 11 in thesystem controller 7A, so that the SYNC discrimination circuit 11 outputsthe mode switching circuit first control signal S9 and supplies the sameto the tuning mode switching circuit 12 when the SYNC signal S2 issupplied at 60 Hz, to change the tuner circuit 2 to the NTSC mode by themode switching signal S11 (step ST6). If the SYNC signal is supplied at50 Hz, on the other hand, it is discriminated as being other than theNTSC system.

When the tuner circuit 2 is set at the NTSC mode, the current tuningdata (data related to the frequency) is stored in the address of thestation number "0" of the memory 6 while information that the currentvideo signal system is the NTSC system is also stored, and the addressof the memory 6 is incremented by one to a station number "1" in orderto store next tuning data (step ST7).

Then, the tuning mode of the tuner circuit 2 is set at the PAL mode at astep ST8, the tuning frequency is increased by a constant amount at thestep ST2 to enter a next tuning operation, the operations through thesteps ST2 to ST8 are repeated, and the tuning is ended upon reaching theupper limit of the tuning frequency. The tuning data obtained by thetuning is supplied to a system for channel selection from the address ofthe memory 6, so that a position number for channel selection isallotted thereto and the tuning mode is ended.

When a discrimination is made on a system other than the NTSC system atthe step ST5, the color discrimination circuit 13 receiving the colorburst signal S8 from the video signal processing circuit 3 makes a colordiscrimination, to discriminate the system to the SECAM system andanother system (step ST9). In the case of the SECAM-L system, the videosignal S1 is hunting since the same is tuned in the PAL mode andfrequency change of the color burst signal S8 cannot be correctlydiscriminated, and hence a system other than the SECAM system isassumed.

When a discrimination on the SECA-,M system is made at the step ST9, thecurrent tuning data (data related to the frequency) is stored in theaddress of the station number "0" of the memory 6 in a state maintainingthe tuning mode at the PAL mode, while information that the currentvideo signal system is the SECAM system is also stored, and the addressof the memory 6 is incremented by one to a station number "1", forstoring next tuning data (step ST7). In the case of the SECAM system,tuning is possible in the PAL mode.

The tuning mode of the tuner circuit 2, which is the PAL mode, may notbe re-set at the step ST8, and the tuning frequency is then increased atthe step ST2 by a constant amount to enter a next tuning operation, sothat the operations through the steps ST2 to ST5, ST9 and ST7 arerepeated and the tuning is ended upon reaching the upper limit of thetuning frequency.

When a determination on a system other than the SECAM system is made atthe step ST9, on the other hand, the color discrimination circuit 13receiving the color burst signal S8 from the video signal processingcircuit 3 again makes a color discrimination, to discriminate the systemto the SECAM system and other system (step ST10). The discrimination atthe step ST10 is made on the assumption of the PAL system when the colorburs signal S8 is 4.43 MHz, otherwise on a system other than the PALsystem.

When a discrimination on the PAL system is made at the step ST10, thetuner circuit 2 stores the current tuning data (data related to thefrequency) in the address of the station number "0" of the memory 6while also storing information that the current video signal system isthe PAL system in a state maintaining the PAL mode, and increments theaddress of the memory 6 by one to a station number "1" for storing nexttuning data (step ST7).

The tuning mode of the tuner circuit 2, which is the PAL mode, may notbe re-set at the step ST8, and the tuning frequency is then increased atthe step ST2 by a constant amount to enter a next tuning operation, sothat the operations through the steps ST2 to ST5. ST9 and ST7 arerepeated and the tuning is ended upon reaching the upper limit of thetuning frequency.

When the discrimination at the step ST10 is on a system other than thePAL system, on the other hand, the color discrimination circuit 13outputs the mode switching circuit second control signal S10 andsupplies the same to the tuning mode switching circuit 12, to change thetuner circuit 2 to the SECAM-L mode by the mode switching signal S11(step ST11).

Then, the color discrimination circuit 13 receiving the color burstsignal S8 from the video signal processing circuit 3 makes a colordiscrimination at a step ST12, to again discriminate the system to theSECAM system and other mode.

When a discrimination on the SECAM system is made at the step ST12, thecurrent tuning data (data related to the frequency) is stored in theaddress of the station number "0" of the memory 6 in a state maintainingthe tuning mode in the SECAM-L mode, while information that the currentvideo signal system is the SECAM system is also stored, and the addressof the memory 6 is incremented by one to a station number "1", forstoring next tuning data (step ST7).

Then, the tuning mode of the tuner circuit 2 is set at the PAL mode at astep ST8, the tuning frequency is increased by a constant amount at thestep ST2 to enter a next tuning operation, the operations through thesteps ST2 to ST5, ST9, ST10, ST11, ST12, ST8 and ST8 are repeated, andthe tuning is ended upon reaching the upper limit of the tuningfrequency. The tuning data obtained by the tuning is supplied to asystem for channel selection from the address of the memory 6, so that aposition number for channel selection is allotted thereto and the tuningmode is ended.

When the discrimination at the step ST12 is on a system other than theSECAM system, on the other hand, the tuning mode is maintained at theSECAM-L mode (step ST13), so that the current tuning data (data relatedto the frequency) is stored in the address of the station number "0" ofthe memory 6 and information that the current video signal system is anundiscriminable other system is also stored, and the address of thememory 6 is incremented by one to the station number "1", for storingnext tuning data (step ST7).

Then, the tuning mode of the tuner circuit 2 is set at the PAL mode atthe step ST8, the tuning frequency is increased by a constant amount atthe step ST2 to enter a next tuning operation, the operations throughthe steps ST2 to ST5, ST9, ST10, ST11, ST12, ST7 and ST8 are repeated,and the tuning is ended upon reaching the upper limit of the tuningfrequency. The tuning data obtained by the tuning is supplied to thesystem for channel selection from the address of the memory 6, so that aposition number for channel selection is allotted thereto and the tuningmode is ended.

The operation following the step ST12 is a system for not stopping thetuning operation also when an undiscriminable signal such as a ghostsignal is received. and the user can arbitrarily designate the videosignal system after the tuning by storing the undiscriminable signal.This is also effective in the case where the signal field is so weakthat the color discrimination circuit 13 cannot discriminate the videosignal system.

As hereinabove described, the automatic tuning apparatus A5 shown inFIG. 14 comprises the SYNC discrimination circuit 11 and the colordiscrimination circuit 13 to discriminate to which one of the PALsystem, the SECAM system, the SECAM-L system and the NTSC system thereceiving signal belongs so that the tuning mode of the tuner circuit 2can be automatically switched, whereby the user may not carry out aswitching operation in response to the video signal system by himself.

Further, it is possible to obtain an automatic tuning apparatus whosetuning operation is not stopped also when an undiscriminable signal suchas a ghost signal is received or the signal field is so weak that thecolor discrimination circuit 13 cannot discriminate the video signalsystem.

The data of the video signal system stored in the memory 6 may be readfrom the memory 6 at need during and after completion of the auto tuningto be used for switching of a chromatic circuit or a tuner circuit orsorting of channel positions, for example.

While the frequency is increased from the lower side to the higher sidein the auto tuning operation of the aforementioned automatic tuningapparatus A5, the frequency may alternatively be reduced from the higherside to the lower side. When there are various frequency bands for VHF,UHF and the like, tuning may be carried out from any frequency band oronly in a specific frequency band. Further, the tuning direction may bevaried with the frequency band.

Sixth Embodiment

FIG. 18 illustrates the structure of an automatic tuning apparatus A6for a VTR according to a sixth embodiment of the present invention.Referring to FIG. 18, structural parts which are identical to those ofthe automatic tuning apparatus AM described with reference to FIG. 14are denoted by the same reference numerals, to omit redundantdescription.

As understood from FIG. 18, the automatic tuning apparatus A6 has such astructure that the color discrimination circuit 13 is removed from theautomatic tuning apparatus A5. Thus, the automatic tuning apparatus A6is an apparatus having a function of discriminating whether the videosignal system of a received signal is the PAL system or the NTSC system.

With reference to a flow chart shown in FIG. 19, the operation of theautomatic tuning apparatus A6 is now described. When a command for autotuning is received from the user, a system controller 7A sets the tuningmode of a tuner circuit 2 at the PAL system, and sets the memory addressof a memory 6 at a station number "0" as initialization (step ST1).

Then, a tuning control signal S3 is transmitted to the tuner circuit 2,to control the same in a direction for increasing the tuning frequencyby a constant amount (step ST2).

At this time, a discrimination is made as to whether or not the currentfrequency reaches the upper limit of the tuning frequency, i.e., whetheror not the tuning is ended (step ST3), so that the tuning is ended ifthe current frequency reaches the upper limit of the tuning frequency,otherwise an AFT signal S4 which is outputted from an AFT detectioncircuit 4 and a SYNC signal S2 indicating presence/absence of a signalseparated by a video signal processing circuit 3 are inputted in thetuning control circuit 5, in order to detect presence/absence of abroadcasting station transmitting the signal of the frequency (stepST4).

If both of the AFT signal S4 and the SYNC signal S2 are supplied at thistime, the tuning control circuit 5 determines that the signal from thebroadcasting station can be received and executes a next step S5. Ifboth of the AFT signal S4 and the SYNC signal S2 are not supplied, onthe other hand, the tuning frequency is increased by a constant amountat the step ST2.

At a step ST5, the SYNC signal S2 from the video signal processingcircuit 3 is transmitted to a SYNC discrimination circuit 11 in thesystem controller 7A. so that the SYNC discrimination circuit 11 outputsa mode switching circuit first control signal S9 and supplies the sameto a tuning mode switching circuit 12 when the SYNC signal S2 issupplied at 60 Hz, to change the tuner circuit 2 to the NTSC mode by amode switching signal S11 (step ST6). If the SYNC signal is supplied at50 Hz, on the other hand, a discrimination is made on a system otherthan the NTSC system.

When the tuner circuit 2 is set at the NTSC mode, current tuning data(data related to the frequency) is stored in the address of the stationnumber "0" of the memory 6 while information that the current videosignal system is the NTSC system is also stored, and the address of thememory 6 is incremented by one to a station number "1" in order to storenext tuning data (step ST7).

Then, the tuning frequency is increased by a constant amount at the stepST2 to enter a next tuning operation, the operations through the stepsST2 to ST7 are repeated, and the tuning is ended upon reaching the upperlimit of the tuning frequency. The tuning data obtained by the tuning issupplied to a system for channel selection from the address of thememory 6, so that a position number for channel selection is allottedthereto and the tuning mode is ended.

When a discrimination on a system other than the NTSC system is made atthe step ST5, the mode switching circuit first control signal S9 isoutputted and supplied to the tuning mode switching circuit 12, tochange the tuner circuit 2 to the PAL mode by the mode switching signalSit (step ST6). Since the tuning mode of the tuner circuit 2 is set atthe PAL mode as initialization, this step ST6 is unnecessary if thetuning mode is not changed to the NTSC mode.

When the tuner circuit 2 is set at the PAL mode, the current tuning data(data related to the frequency) is stored in the address of the stationnumber "0" of the memory 6 while information that the current videosignal system is the PAL system is also stored, and the address of thememory 6 is incremented by one to a station number "1" in order to storenext tuning data (step ST7).

Then, the tuning frequency is increased by a constant amount at the stepST2 to enter a next tuning operation, the operations through the stepsST2 to ST7 are repeated, and the tuning is ended upon reaching the upperlimit of the tuning frequency. The tuning data obtained by the tuning issupplied to the system for channel selection from the address of thememory 6, so that a position number for channel selection is allottedthereto and the tuning mode is ended.

As hereinabove described, the automatic tuning apparatus A6 shown inFIG. 18 comprises the SYNC discrimination circuit 11 to discriminatewhether the video signal system of the received signal is the PAL systemor the NTSC system so that the tuning mode of the tuner circuit 2 can beautomatically switched, whereby the user may not carry out a switchingoperation in response to the video signal system by himself.

The remaining functions are similar to those of the automatic tuningapparatus A5, and hence redundant description is omitted.

Seventh Embodiment

FIG. 20 illustrates the structure of an automatic tuning apparatus A7for a VTR according to a seventh embodiment of the present invention.Referring to FIG. 20, a system controller 7B comprising a tuning controlcircuit A, a memory circuit 6 and a tuning mode switching circuit 12 isprovided in place of the system controller 7A of the automatic tuningapparatus A5 described with reference to FIG. 14. The remainingstructural parts which are identical to those of the automatic tuningsapparatus A5 are denoted by the same reference numerals, to omitredundant description.

As understood from FIG. 20, the automatic tuning apparatus A7 has such astructure that the SYNC discrimination circuit 11 is removed from theautomatic tuning apparatus A5. Thus, the automatic tuning apparatus A7is an apparatus having a function of discriminating to which one of thePAL system, the SECAM system and the SECAM-L system the video signalsystem of a received signal belongs.

With reference to a flow chart shown in FIG. 21, the operation of theautomatic tuning apparatus A7 is now described. When a command for autotuning is received from the user, the system controller 7B sets thetuning mode of a tuner circuit 2 at the PAL system, and sets the memoryaddress of the memory 6 at a station number "0" as initialization (stepST1).

Then, a tuning control signal S3 is transmitted to the tuner circuit 2,to control the same in a direction for increasing the tuning frequencyby a constant amount (step ST2).

At this time, a discrimination is made as to whether or not the currentfrequency reaches the upper limit of the tuning frequency, i.e., whetheror not the tuning is ended (step ST3), so that the tuning is ended ifthe current frequency reaches the upper limit of the tuning frequency,otherwise an AFT signal S4 which is outputted from an AFT detectioncircuit 4 and a SYNC signal S2 indicating presence/absence of a signalseparated by a video signal processing circuit 3 are inputted in thetuning control circuit 5, in order to detect presence/absence of abroadcasting station transmitting a signal of the frequency (step ST4).

If both of the AFT signal S4 and the SYNC signal S2 are supplied at thistime, the tuning control circuit 5 determines that the signal from thebroadcasting station can be received and executes a next step S5. Ifboth of the AFT signal S4 and the SYNC signal S2 are not supplied, onthe other hand, the tuning frequency is increased by a constant amountat the step ST2.

At a step ST5, a color discrimination circuit 13 receiving a color burstsignal S8 from the video signal processing circuit 3 carries out a colordiscrimination, to discriminate the system to the SECAM system andanother system. In the case of the SECAM-L system, a video signal S1 ishunting since the same is tuned in the PAL mode and frequency change ofthe color burst signal S8 cannot be correctly discriminated, and hencethe system is assumed to be that other than the SECAM system.

When a discrimination on the SECANM system is made at the step ST5, onthe other hand, current tuning data (data related to the frequency) isstored in the address of the station number "0" of the memory 6 whileinformation that the current video signal system is the SECAM system isalso stored, and the address of the memory 6 is incremented by one to astation number "1" in order to store next tuning data (step ST6). In thecase of the SECAM system, tuning is possible in the PAL mode.

No re-setting at the step ST7 is required at a step ST7 since the tuningmode of the tuner circuit 2 is the PAL mode, and the tuning frequency isthen increased by a constant amount at the step ST2 to enter a nexttuning operation, the operations through the steps ST2 to ST7 arerepeated and the tuning is ended upon reaching the upper limit of thetuning frequency.

When a determination on a system other than the SECAM system is made atthe step ST5, on the other hand, the color discrimination circuit 13receiving the color burst signal S8 from the video signal processingcircuit 3 again makes a color discrimination, to discriminate the systemto the PAL system and another system (step ST8). The discrimination atthe step ST8 is made on the assumption of the PAL system when the colorburst signal S8 is 4.43 MHz, otherwise on a system other than the PALsystem.

When the PAL system is discriminated at the step ST8, the tuner circuit2 stores the current tuning data (data related to the frequency) in theaddress of the station number "0" of the memory 6 while also storinginformation that the current video signal system is the PAL system in astate maintaining the PAL mode, and increments the address of the memory6 by one to a station number "1" for storing next tuning data (stepST6).

No re-setting at the step ST7 is required since the tuning mode of thetuner circuit 2 is the PAL mode, and the tuning frequency is thenincreased by a constant amount at the step ST2 to enter a next tuningoperation, the operations through the steps ST2 to ST5, ST8, ST6 and ST7are repeated and the tuning is ended upon reaching the upper limit ofthe tuning frequency.

When a discrimination on a system other than the PAL system is made atthe step ST8, on the other hand, the color discrimination circuit 13outputs a mode switching circuit second control signal S10 and suppliesthe same to the tuning mode switching circuit 12, to change the tunercircuit 2 to the SECAM-L mode by a mode switching signal S11 (step ST9).

Then, the color discrimination circuit 13 receiving the color bustsignal SS from the video signal processing circuit 3 carries out a colordiscrimination to again discriminate the system to the SECAM system andanother system at a step ST10.

When the SECAM system is discriminated at the step ST10, the currenttuning data (data related to the frequency) is stored in the address ofthe station number "0" of the memory 6 while information that thecurrent video signal system is the SECAM system is also stored in astate maintaining the tuning mode in the SECAM-L mode, and the addressof the memory 6 is incremented by one to a station number "1" forstoring next tuning data (step ST6).

Then, the tuning mode of the tuner circuit 2 is set at the PAL mode atthe step ST7, the tuning frequency is increased by a constant amount atthe step ST2 to enter a next tuning operation, the operations throughthe steps ST2 to ST5, ST8, ST9, St10, ST6 and ST7 are repeated, and thetuning is ended upon reaching the upper limit of the tuning frequency.The tuning data obtained by the tuning is supplied to a system forchannel selection from the address of the memory 6, so that a positionnumber for channel selection is allotted thereto and the tuning mode isended.

When a discrimination on a system other than the SECAM system is made atthe step ST10, on the other hand, the tuning mode is maintained at theSECAM-L mode (step ST11) and the current tuning data (data related tothe frequency) is stored in the address of the station number "0" of thememory 6 and information that the current video signal system is anundiscriminable other system is also stored, and the address of thememory 6 is incremented by one to the station number "1" for storingnext tuning data (step ST6).

Then, the tuning mode of the tuner circuit 2 is set at the PAL mode atthe step ST7, the tuning frequency is increased by a constant amount atthe step ST2 to enter a next tuning operation, the operations throughthe steps ST2 to ST5, ST8, ST9, St10, ST6 and ST7 are repeated, and thetuning is ended upon reaching the upper limit of the tuning frequency.The tuning data obtained by the tuning is supplied to the system forchannel selection from the address of the memory 6, so that a positionnumber for channel selection is allotted thereto and the tuning mode isended.

The operation following the step ST10 is a system for not stopping thetuning operation also when an undiscriminable signal such as a ghostsignal is received, and the user can arbitrarily designate the videosignal system after the tuning by storing the undiscriminable signal.This is also effective in the case where the signal field is so weakthat the color discrimination circuit 13 cannot discriminate the videosignal system.

As hereinabove described, the automatic tuning apparatus A7 shown inFIG. 20 comprises the color discrimination circuit 13 to discriminate towhich one of the PAL system, the SECAM system and the SECAM-L system thevideo signal system of the received signal belongs so that the tuningmode of the tuner circuit 2 can be automatically switched, whereby theuser may not carry out a switching operation in response to the videosignal system by himself.

Further, it is possible to obtain an automatic tuning apparatus whosetuning operation is not stopped also when an undiscriminable signal suchas a ghost signal is received or the signal field is so weak that thecolor discrimination circuit 13 cannot discriminate the picture signalsystem.

The remaining functions are similar to those of the automatic tuningapparatus A5, and hence redundant description is omitted.

Modifications

The structures of the automatic tuning apparatus A1 to A4 according tothe first to fourth embodiments may be added to the aforementionedautomatic tuning apparatus A5 to A7 according to the fifth to seventhembodiments of the present invention for storing broadcasting stationinformation, noise data and picture definition data in the memories anddisplaying the same on the receiver screens.

In a structure therefor, the text data decoder circuit 10, the noisedetection circuit 20 and the picture definition detection circuit 30 areprovided to receive the video signal S1 outputted from the tuner circuit2 and outputs are supplied to the tuning, control circuit 5, while theCG circuit 40 is provided between the output of the video signalprocessing circuit 3 and the video signal output terminal 9.

Eighth Embodiment

FIG. 22 illustrates the structure of an automatic tuning apparatus A8for a VTR according to an eighth embodiment of the present invention.Referring to FIG. 22, numeral 2A denotes a tuner circuit which isconnected to an antenna 1, numeral 4 denotes an AFT detection circuitwhich receives a signal from the tuner circuit 2 for detectingpresence/absence of a broadcasting station, numeral 5A denotes a tuningcontrol circuit for controlling the tuning operation of the tunercircuit 2A, and numeral 6 denotes a memory which is connected to thetuning control circuit 5A, and a system control circuit 7C is formed bythe tuning control circuit 5A and the memory 6. A sound processor 60 isconnected to the tuner circuit 2A.

The sound processor 60 is formed by sound demodulation circuitsreceiving a sound intermediate frequency signal (hereinafter referred toas an SIF signal) S12 which is outputted from the tuner circuit 2A anddemodulating the same to a sound, and voltage control oscillators(hereinafter referred to as VCOs).

The sound processor 60 is provided therein with FM sound demodulationcircuits 61, 62, 63 and 64 carrying out FM detection and an AM sounddemodulation circuit 65 carrying out AM detection so that the SIF signalis supplied thereto in parallel with each other, a VCO 610 having anoscillation frequency of 4.5 MHz is connected to the FM sounddemodulation circuit 61, a VCO 620 having an oscillation frequency of5.5 MHz is connected to the FM sound demodulation circuit 62, a VCO 630having an oscillation frequency of 6.0 MHz is connected to the FM sounddemodulation circuit 63, a VCO 640 having an oscillation frequency of6.5 MHz is connected to the FM sound demodulation circuit 64 and the AMsound demodulation circuit 65, and outputs of the FM sound demodulationcircuits 61, 62, 63 and 64 and the AM sound demodulation circuit 65 aresupplied to the tuning control circuit 5A.

The FM sound demodulation circuits 61, 62, 63 and 64 are formed by FMdetection circuits of a quadrature system or the like while the AM sounddemodulation circuit 65 is formed by an AM detection circuit, andredundant description is omitted since both are well-known circuits.Redundant description is omitted also as to the VCOs, which are ingeneral structures.

With reference to flow charts shown in FIG. 23 and 24, the operation ofthe automatic tuning apparatus A8 is now described. When a command forautomatic tuning is received from the user, the tuning control circuit5A transmits a tuning control signal S3 to the tuner circuit 2A, tocontrol the same to a direction for increasing the tuning frequency by aconstant amount (step ST1).

In order to detect presence/absence of a sound signal (sound carrier) ofa broadcasting station received by the antenna 1, an AFT signal S4 whichis outputted from the AFT detection circuit 4 is inputted in the tuningcontrol circuit 5A (step ST2).

If no AFT signal S4 is supplied at the step ST2, a discrimination ismade as to whether or not the current frequency reaches the upper limitof the tuning frequency, i.e., whether or not the tuning is ended (stepST3), to complete the tuning if the current frequency reaches the upperlimit of the tuning frequency, otherwise carrying out the operation atthe step ST1 again.

If the AFT signal S4 is supplied at the step ST2, on the other hand, theSIF signal S12 which is outputted from the tuner circuit 2A is suppliedto the FM sound demodulation circuit 61 (step ST4). The VCO 610 havingthe oscillation frequency of 4.5 MHz is connected to the FM sounddemodulation circuit 61, and the sound signal is demodulated if a soundcarrier matching with the frequency 4.5 MHz of the VCO 610 is present inthe supplied SIF signal S12 (step ST5), and transmitted to the systemcontroller 7C, and the current VCO frequency is stored in the memory 6with the tuning data (step ST6), and operations following the step ST1are carried out.

If there is no sound carrier matching with the frequency 4.5 MHz of theVCO 610 in the supplied SIF signal S12, on the other hand, the FM sounddemodulation circuit 62 makes a determination as to presence/absence ofa sound carrier matching with the frequency 5.5 MHz of the VCO 620 inthe supplied SIF signal S12 (step ST7), so that the sound signal isdemodulated if the sound carrier is present (step ST5) and transmittedto the system controller 7C, and the current VCO frequency is stored inthe memory 6 with the tuning data (step ST6), and the operationsfollowing the step ST1 are carried out.

If there is no sound carrier matching with the frequency 5.5 NlHz of theVCO 620 in the supplied SIF signal S12, the FM sound demodulationcircuit 63 makes a determination as to presence/absence of a soundcarrier matching with the frequency 6.0 MHz of the VCO 630 in thesupplied SIF signal S12 (step ST8), so that the sound signal isdemodulated if the sound carrier is present (step ST5) and transmittedto the system controller 7C, and the current VCO frequency is stored inthe memory 6 with the tuning data (step ST6), and the operationsfollowing the step ST1 are carried out, similarly to the above.

If there is no sound carrier matching with the frequency 6.0 MHz of theVCO 630 in the supplied SIF signal S12, the FM sound demodulationcircuit 64 makes a determination as to presence/absence of a soundcarrier matching with the frequency 6.5 MHz of the VCO 640 in thesupplied SIF signal S12 (step ST9), so that the sound signal isdemodulated if the sound carrier is present (step ST5) and transmittedto the system controller 7C, and the current VCO frequency is stored inthe memory 6 with the tuning data (step ST6), and the operationsfollowing the step ST1 are carried out, similarly to the above.

If there is no sound carrier matching with the frequency 6.5 MHz of theVCO 640 in the supplied SIF signal S12, the AM sound demodulationcircuit 65 makes a determination as to presence/absence of a soundcarrier matching with the frequency 6.5 MHz of the VCO 640 in thesupplied SIF signal S12 (step ST10), so that the sound signal isdemodulated if the sound carrier is present (step ST5) and transmittedto the system controller 7C, and the current VCO frequency is stored inthe memory 6 with the tuning data (step ST6), and the operationsfollowing the step ST1 are carried out, similarly to the above.

If there are no sound carriers matching with the frequencies of therespective VCOs at the steps ST4 to ST8, a determination is made as towhether or not the tuning frequency reaches the upper limit (step ST11)to end the tuning operation if the tuning frequency reaches the upperlimit while repeating the operation at the step ST1 if the same does notreach the upper limit.

Thus, the sound signal system of the received signal can be detecteddepending on with which one of the FM sound demodulation circuits 61 to64 and the AM sound demodulation circuit 65 the frequency of the SIFsignal S12 matches. When the video signal system is the PAL system orthe SECAM system, for example, an output of 6.0 MHz appears when thesound signal system is the I system, an output of 5.5 MHz appears whenthe sound signal system is the B/G system, and an output of 6.5 MHzappears when the sound signal system is the D/K system. Further, anoutput of 4.5 MHz appears when the sound signal system is an M system,and the current video signal system is the NTSC system.

According to the automatic tuning apparatus A8 of this embodiment,therefore, it is possible to further finely classify the received signalby discriminating not only the video signal system but the sound signalsystem. Due to such function, it is possible to automatically cope witheach broadcasting station in receiving around the boundary, for example,when a plurality of broadcasting stations of the same video signalsystem are present and respective sound signal systems are differentfrom each other.

Further, the apparatus comprises a plurality of sound demodulationcircuits and VCOs having different oscillation frequencies provided forthe respective ones of the sound demodulation circuits, wherebydiscriminations of the sound signal systems are so parallel-processedthat the time required for the discriminations can be reduced.

While a discrimination of the video signal system is not mentioned as tothe aforementioned automatic tuning apparatus A8, the discrimination ofthe video signal system is enabled by combining the same with theautomatic tuning apparatus A5 to A7 shown in the fifth to seventhembodiments according to the present invention.

The result of the sound signal system may be read from the memory 6during or after completion of the auto tuning to be used for switchingof a chromatic circuit or a video system tuner circuit or sorting ofchannel positions, for example, and this discriminating operation is notrestricted to the auto tuning but may be carried out anytime ifnecessary.

Ninth Embodiment

FIG. 25 illustrates the structure of an automatic tuning apparatus A9for a VTR according to a ninth embodiment of the present invention.Referring to FIG. 25, numeral 2A denotes a tuner circuit which isconnected to an antenna 1, numeral 4 denotes an AFT detection circuitwhich receives a signal from the tuner circuit 2A for detectingpresence/absence of a broadcasting station, numeral 5 denotes a tuningcontrol circuit for controlling the tuning operation of the tunercircuit 2A, and numeral 6 denotes a memory circuit which is connected tothe tuning control circuit 5, and a system control circuit 7 is formedby the tuning control circuit 5 and the memory 6. A sound demodulationcircuit 70 receiving an SIF signal S12 and demodulating the same to asound is connected to the tuner circuit 2A, while a VCO 80 which iscontrolled by a VCO control signal S13 outputted from the tuning controlcircuit 5 for outputting a clock signal S14 of a prescribed frequency isconnected to the sound demodulation circuit 70. A sound signal S15outputted from the sound demodulation circuit 70 is supplied to a sounddetection circuit 90, and a detected sound detection signal S16 issupplied to the tuning control circuit 5.

The sound demodulation circuit 70 is a known circuit which is formed byan FM detection circuit of the quadrature system or the like, and henceredundant description is omitted. As to the VCO 80 outputting the clocksignal S14 in the range of 5.5 MHz to 7.0 MHz, redundant description isomitted since its structure is general.

FIG. 26 shows the structure of the sound detection circuit 90. As shownin FIG. 26, the sound detection circuit 90 is formed by a half-waverectification circuit 901 and a pulse shaping circuit 902, so that the(demodulated) sound signal S15 is half-wave rectified by the half-waverectification circuit 901 and supplied to the pulse shaping circuit 902.The pulse shaping circuit 902 pulses the half-wave rectified soundsignal and outputs the same as a "high" or "low" dc voltage signal(sound detection signal S16).

With reference to a flow chart shown in FIG. 27, the operation of theautomatic tuning apparatus A9 is now described. The tuning controlcircuit 5 which receives a command for automatic tuning from the userfirst sets the oscillation frequency of the VCO 80 at 5.5 MHz asinitialization (step ST1).

Then the tuning control circuit 5 transmits a tuning control signal S3to the tuner circuit 2A, to control the same in a direction forincreasing the tuning frequency by a constant amount (step ST2).

Then, an AFT signal S4 which is outputted from the MT detection circuit4 is inputted in the tuning control circuit 5, in order to detectpresence/absence of a broadcasting station transmitting a signal of thefrequency (step ST3).

If a sound carrier matching with the frequency 5.5 MHz of the VCO 80 isincluded in a supplied SIF signal S12, the same is demodulated into thesound signal S15 and outputted in a state maintaining the tuningfrequency, when the AFT signal S4 is supplied (step ST4).

The demodulated sound signal S15 is transmitted to the sound detectioncircuit 90, and pulsed to be transmitted to the system controller 7 asthe sound detection signal S16 (step ST5).

If the sound detection signal S16 is "high", the current tuning data andthe oscillation frequency of the VCO 80 are stored in the memory 6 ofthe system controller 7 as address data, and the address for storage isthen incremented by one to continue the tuning operation (step ST6).

The operations through the steps ST1 to ST6 are carried until the upperlimit of the tuning frequency is reached, and the tuning mode is endedupon reaching the upper limit (step ST7).

If the sound detection signal S16 is "low" at the step ST5, on the otherhand, the oscillation frequency of the VCO 80 is increased by 0.5 MHz(step ST8), and the sound signal S15 demodulated by the sounddemodulation circuit 70 is transmitted to the sound detection circuit 90if the current oscillation frequency of the VCO 80 is not 7.0 MHz (stepST9), so that the sound signal S15 is pulsed.

When the sound detection signal S16 is converted to "high" by changingthe oscillation frequency of the VCO 80, the current tuning data and theoscillation frequency of the VCO 80 are stored in the memory 6 of thesystem controller 7 as address data, and the address for storage is thenincremented by one to continue the tuning operation (step ST6).

If the sound detection signal S16 remains "low" upon change of theoscillation frequency of the VCO 80, the process returns to the step ST1when the frequency of the VCO reaches 7.0 MHz, to end the tuning.

As hereinabove described, the automatic tuning apparatus A9 comprisesthe VCO 80 outputting the clock signal S14 in the range of 5.5 MHz to7.0 MHz and the sound detection circuit 90, whereby the system of thesound signal can be discriminated without providing a plurality of thesound demodulation circuits 70, and the apparatus is suitable forminiaturization with a small number of elements.

Further, discrimination of the video signal system is also enabled bycombining the automatic tuning apparatus A9 with the automatic tuningapparatus A5 to A7 according to the fifth to seventh embodiments of thepresent invention.

While the AFT signal S4 which is outputted from the AFT detectioncircuit 4 is employed in the aforementioned embodiment in order todetect presence/absence of the broadcasting station, determinationaccuracy in the tuning, can be improved by employing an SIF signal S12outputted from the tuner circuit 2A.

The result of the discrimination of the sound carrier system may be readfrom the memory 6 in or after completion of the automatic tuning to beused for switching of a chromatic circuit or a video system tunercircuit or sorting of channel positions, for example, and thisdiscriminating operation is not restricted to the automatic tuning butmay be carried out anytime if necessary.

Tenth Embodiment

FIG. 28 shows the structure of an automatic tuning apparatus A10 for aVTR according to a tenth embodiment of the present invention. Referringto FIG. 28, numeral 2A denotes a tuner circuit which is connected to anantenna 1, numeral 3 denotes a video signal processing circuit includinga SYNC separation circuit which receives a composite video signal S1from the tuner circuit 2A for carrying out signal processing, numeral 4denotes an AFT detection circuit receiving a signal from the tunercircuit 2A for detecting presence/absence of a broadcasting station,numeral 5 denotes a tuning control circuit for controlling the tuningoperation of the tuner circuit 2A, numeral 6 denotes a memory which isconnected to the tuning control circuit 5, and numeral 100 denotes asorting control circuit for sorting tuning data stored in the memory 6along prescribed position numbers, which is controlled by a SYNC signalS2 from the video signal processing circuit 3.

A system controller 7D is formed by the tuning control circuit 5, thememory 6 and the sorting control circuit 100. Numeral 10 denotes a textdata decoder circuit which receives the video signal S1 and extracts ateletext signal S5, which is information from the broadcasting station,from the video signal S1 for supplying the same to the memory 6. Numeral8 denotes an input signal system switch for switching the operation ofthe tuning control circuit 5 in response to the video signal system ofthe input signal.

With reference to FIG. 29, the structure of the sorting control circuit100 is now described. The sorting control circuit 100, which is formedby software, is indicated as hardware in FIG. 29.

Referring to FIG. 29, the sorting control circuit 100 comprises aposition number pointer 110 for providing a position number for channelselection, a station number pointer 120 for providing a broadcastingstation number (station number), a first register 130 readingbroadcasting station information (station ID) from a sorting referencememory 61 which is previously provided in the memory 6, a secondregister 140 reading the station ID from a tuning data memory 62 storedin the memory 6 by a tuning operation, a comparison part 150 comparingthe station IDs read by the first and second registers 130 and 140respectively with each other, and a determination part 160 determiningthe result of the comparison and instructing provision numbers to theposition number pointer 110 and the station number pointer 120, forstoring a sorting result having corresponding position and stationnumbers by sorting in a sorting result memory 63 provided in the memory6.

With reference to flow charts shown in Figs. 30 and 31, the operation ofthe automatic tuning apparatus A10 is now described. When a command forauto tuning is received from the user, the system controller 7D sets thememory address of the memory 6 at a station number "0" (step ST1).

Then, a tuning control signal S3 is transmitted to the tuner circuit 2A,to control the same in a direction for increasing the tuning frequencyby a constant amount (step ST2). At this time, an AFT signal S4 which isoutputted from an AFT detection circuit 4 and a SYNC signal S2indicating presence/absence of a signal separated by the video signalprocessing circuit 3 are inputted in the tuning control circuit 5 fordetecting presence/absence of a broadcasting station transmitting asignal of the frequency, to make a discrimination (step ST3).

When both of the AFT signal S4 and the SYNC signal S2 are supplied atthis point of time, the tuning control circuit 5 determines that thesignal from the broadcasting station can be received, and the currenttuning data is stored in the address of the station number "0" in thememory 6 (step ST4).

At the same time, the text data decoder circuit 10 decodes textinformation which is superposed on a blanking period of the signal fromthe composite video signal S1, so that the decoded teletext signal S5 isinputted in the tuning control circuit 5 (step ST5).

The tuning control circuit 5 extracts and discriminates broadcastingstation information (station ID) from the teletext signal S5 (step ST6),and stores the same in the address of the station number "0" in thememory 6, similarly to the data related to the frequency (step ST7).

Then, the address of the memory 6 is incremented by one to a stationnumber "1" in order to store next tuning data, for entering a nexttuning operation (step ST8).

If both of the AFT signal S4 and the SYNC signal S2 are not supplied atthe step ST3, on the other hand, a discrimination is made as to whetheror not the current frequency reaches the upper limit of the tuningfrequency, i.e., whether or not the tuning is ended (step ST9).

If the current frequency does not reach the upper limit of the tuningfrequency, the operation at the step ST2 is carried out again and theoperations through the steps ST2 to ST8 are repeated until the upperlimit of the tuning frequency is reached.

If the upper limit of the tuning frequency is reached at the step ST9,on the other hand, the process enters a sorting operation of the sortingcontrol circuit 100. First, the sorting reference memory 61 in thememory 6 is activated, a station ID corresponding to a previously setposition number is read (step ST10), and the station ID indicated by theposition number pointer 110 is loaded in the first register 130 (stepST11).

Then, the tuning data memory 62 in the memory 6 is activated, a stationID corresponding to the station number is read, and a station IDindicated by the station number pointer 120 is loaded in the secondregister 140, so that the comparison part 150 compares the station IDswhich are loaded in the first and second registers 130 and 140respectively with each other and the determination part 160 makes adetermination (step ST12).

When the station IDs match with each other at the step ST12, the stationnumber is stored in the sorting result memory 63 in the memory 6 incorrespondence to the position number (step ST13).

Then, the position number is incremented by one in the position numberpointer 110 (step ST14).

Then, the station number pointer 120 determines whether or not thecurrent station number reaches the upper limit (step ST15).

Also when the station IDs mismatch with each other at the step ST12, theoperation at the step ST15 is carried out.

If the current station number does not reach the upper limit at the stepST15, the station number is incremented by one in the station numberpointer 120, to carry out the operation following the step ST12 again(step ST16).

When the current station number reaches the upper limit, on the otherhand, the position number pointer 110 determines whether or not allstation IDs are sorted, i.e., whether or not the position number reachesthe upper limit (step ST17).

If a determination is made at the step ST17 that all station IDs aresorted, the sorting operation is ended.

If all station IDs are not sorted, on the other hand, the positionnumber pointer 110 increments the position number by one, to carry outthe operation following the step ST11 again (step ST18).

The aforementioned automatic tuning apparatus A10 comprises the sortingcontrol circuit 100 so that a broadcasting station of a predeterminedstation ID is automatically set for each position number by a sortingoperation and the user may not set the broadcasting station incorrespondence to the position number, whereby the burden imposed on theuser can be reduced.

When no station ID corresponding to the station number is found in theaforementioned sorting operation, this position is not selected butprocessing such as skipping is carried out.

Eleventh Embodiment

FIG. 32 shows the structure of an automatic tuning apparatus A11 for aVTR according to an eleventh embodiment of the present invention.Referring to FIG. 32, structural parts identical to those of theautomatic tuning apparatus A10 described with reference to FIG. 28 aredenoted by the same reference numerals, to omit redundant description.

Referring to FIG. 32, a user input control circuit 200 provided for theuser for setting sorting order is connected to a memory 6, and a systemcontroller 7E is formed by a tuning control circuit 5, the memory 6, asorting control circuit 100 and the user input control circuit 200. Akey input unit 300 for the user for inputting setting is connected tothe user input control circuit 200.

With reference to FIG. 33, the structure of the user input controlcircuit 200 is now described. Referring to FIG. 33, the user inputcontrol circuit 200 comprises a key interface circuit 210 fortransferring signals with the key input unit 300, a position numberregister 220 and a station name register 230 which are connected to thekey interface circuit 210, and a station ID conversion circuit 240 and adisplay unit 250 which are connected to the station name register 230,while the position number register 220 is connected to a sortingreference memory 61 of the memory 6 through a position number pointer110 of the sorting control circuit 100 and the station ID conversioncircuit 240 is also connected to the sorting reference memory 61.

The operation of the user input control circuit 200 is now described.When the user inputs broadcasting station information (the broadcastingstation name, the broadcasting station name code etc.) from the keyinput unit 300 in correspondence to the position number, the positionnumber and the broadcasting information are supplied to the positionnumber register 220 and the station name register 230 respectively, sothat the position number is supplied to the sorting reference memory 61by the position number pointer 110 and the broadcasting stationinformation is converted to a station ID by the station ID conversioncircuit 240 and supplied to the sorting reference memory 61 to be storedtherein. The broadcasting station information is displayed on thedisplay unit 250.

With reference to flow charts shown in FIGS. 34 and 35, the operation ofthe automatic tuning apparatus A11 is now described. First, the userinputs broadcasting station information (the broadcasting station name,the broadcasting station name code etc.) through the key input unit 300in correspondence to the position number, and sets the sorting order(step ST1).

Then, the system controller 7E receives a command for auto tuning andsets the memory address of the memory 6 at a station number "0" (stepST2).

Then, a tuning control signal S3 is transmitted to a tuner circuit 2A,to control the same in a direction for increasing the tuning frequencyby a constant amount (step ST3). At this time, an AFT signal S4 which isoutputted from an AFT detection circuit 4 and a SYNC signal S2indicating presence/absence of a signal separated by a video signalprocessing circuit 3 are inputted in the tuning control circuit 5 fordetecting presence/absence of a broadcasting station transmitting asignal of the frequency, to make a discrimination (step ST4).

When both of the AFT signal S4 and the SYNC signal S2 are supplied atthis point of time, the tuning control circuit 5 determines that thesignal from the broadcasting station can be received, and the currenttuning data is stored in the address of the station number "0" in thememory 6 (step ST5).

At the same time, a text data decoder circuit 10 decodes textinformation which is superposed on a blanking period of a compositevideo signal S1, so that a decoded teletext signal S5 is inputted in thetuning control circuit 5 (step ST6).

The tuning control circuit 5 extracts and discriminates broadcastingstation information (station ID) from the teletext signal S5 (step ST7),and stores the same in the address of the station number "0" in thememory 6, similarly to data related to the frequency (step ST8).

Then, the address of the memory 6 is incremented by one to a stationnumber "1" in order to store next tuning data, for entering a nexttuning operation (step ST9).

If both of the AFT signal S4 and the SYNC signal S2 are not supplied atthe step ST4, on the other hand, a discrimination is made as to whetheror not the current frequency reaches the upper limit of the tuningfrequency, i.e., whether or not the tuning is ended (step ST10).

If the current frequency does not reach the upper limit of the tuningfrequency, the operation at the step ST3 is carried out again and theoperations through the steps ST3 to ST9 are repeated until the upperlimit of the tuning frequency is reached.

If the upper limit of the tuning frequency is reached at the step ST10,on the other hand, the process enters a sorting operation of the sortingcontrol circuit 100. First, the sorting reference memory 61 in thememory 6 is activated, a station ID corresponding to a previously setposition number is read (step ST11), and a station ID indicated by theposition number pointer 110 is loaded in the first register 130 (stepST12).

Then, the tuning data memory 62 in the memory 6 is activated, a stationID corresponding to the station number is read, and a station IDindicated by the station number pointer 120 is loaded in the secondregister 140, so that the comparison part 150 compares the station IDswhich are loaded in the first and second registers 130 and 140respectively with each other and the determination part 160 makes adetermination (step ST13).

When the station IDs match with each other at the step ST13, the stationnumber is stored in the sorting result memory 63 in the memory 6 incorrespondence to the position number (step ST14).

Then, the position number is incremented by one in the position numberpointer 110 (step ST15).

Then, the station number pointer 120 determines whether or not thecurrent station number reaches the upper limit (step ST16).

Also when the station IDs mismatch with each other at the step ST13, theoperation at the step ST16 is carried out.

If the current station number does not reach the upper limit at the stepST15, the station number is incremented by one in the station numberpointer 120, to carry out the operation following the step ST12 again(step ST17).

When the current station number reaches the upper limit, on the otherhand, the position number pointer 110 determines whether or not allstation IDs are sorted, i.e., whether or not the position number reachesthe upper limit (step ST18).

If a determination is made at the step ST18 that all station IDs aresorted, the sorting operation is ended.

If all station IDs are not sorted, on the other hand, the positionnumber pointer 110 increments the position number by one, to carry outthe operation following the step ST12 again (step ST19).

The aforementioned automatic tuning apparatus A11 comprises the userinput control circuit 200 so that the user sorts desired broadcastingstations along the sorting order set by him, whereby the broadcastingstations of the station IDs desired by the user are automatically set atthe respective position numbers. Although a burden is imposed on theuser in the point that he must set the position numbers and thebroadcasting station information, a broadcasting station to beautomatically tuned at the user's necessity can be set from receivablebroadcasting stations in an area where receivable broadcasting stationsare limited.

Twelfth Embodiment

FIG. 36 shows the structure of an automatic tuning apparatus A12 for aVTR according to a twelfth embodiment of the present invention.Referring to FIG. 36, structural parts identical to those of theautomatic tuning apparatus A10 described with reference to FIG. 28 aredenoted by the same reference numerals, to omit redundant description.

Referring to FIG. 36, a video signal system discrimination circuit 400receiving a SYNC signal S2 outputted from a video signal processingcircuit 3 and a color burst signal (identical signal) S8 fordiscriminating to which one of the NTSC system, the PAL system, theSECAM system and the SECAM-L system the video signal system belongs isconnected to a memory 6.

A system controller 7D is formed by a tuning control circuit 5, thememory 6 and a sorting control circuit 100.

The video signal system discrimination circuit 400 is formed by a SYNCdiscrimination circuit 11, which is shown in the automatic tuningapparatus A5 described with reference to the fifth embodiment of thepresent invention, for discriminating whether the picture signal systemis the NTSC system or another system through the number of the SYNCsignal, and a color discrimination circuit 13 receiving a color bustsignal (identical signal) S8 which is one of outputs of the video signalprocessing circuit 3 for discriminating whether the video signal systemis the PAL system or the SECAM system, and redundant description isomitted since the details of the SYNC discrimination circuit 11 and thecolor discrimination circuit 13 have already been described, while theoutput of the video signal system discrimination circuit 400 is referredto as "discrimination result of the video signal system" in thefollowing description. Further, the sorting control circuit 100 employsthe video signal system in place of broadcasting station information(station ID), and hence "station ID" in the automatic tuning apparatusA10 described with reference to the tenth embodiment of the presentinvention is re-read as "video signal system".

With reference to flow charts shown in FIGS. 37 and 38, the operation ofthe automatic tuning apparatus A12 is now described. When a command forauto tuning is received from the user, the system controller 7D sets thememory address of the memory 6 at a station number "0" (step ST1).

Then, a tuning control signal S3 is transmitted to a tuner circuit 2A,to control the same in a direction for increasing the tuning frequencyby a constant amount (step ST2). At this time, an AFT signal S4 which isoutputted from an AFT detection circuit 4 and a SYNC signal S2indicating presence/absence of a signal separated by the video signalprocessing circuit 3 are inputted in the tuning control circuit 5 fordetecting presence/absence of a broadcasting station transmitting asignal of the frequency, to make a discrimination (step ST3).

When both of the AFT signal S4 and the SYNC signal S2 are supplied atthis point of time, the tuning control circuit 5 determines that thesignal from the broadcasting station can be received, and the currenttuning data is stored in the address of the station number "0" in thememory 6 (step ST4).

At the same time, the discrimination result of the video signal systemis obtained from the video signal system discrimination circuit 400(step ST5).

The discrimination result of the video signal system is stored in theaddress of the station number "0" in the memory 6, similarly to datarelated to the frequency (step ST6).

Then, the address of the memory 6 is incremented by one to a stationnumber "1" in order to store next tuning data for entering a next tuningoperation (step ST7).

If both of the AFT signal S4 and the SYNC signal S2 are not supplied atthe step ST3, on the other hand, a discrimination is made as to whetheror not the current frequency reaches the upper limit of the tuningfrequency, i.e., whether or not the tuning is ended (step ST8). If thecurrent frequency does not reach the upper limit of the tuningfrequency, the operation at the step ST2 is carried out again and theoperations through the steps ST2 to ST7 are repeated until the upperlimit of the tuning frequency is reached.

If the upper limit of the tuning frequency is reached at the step ST8,the process enters a sorting operation of the sorting control circuit100. First, a sorting reference memory 61 in the memory 6 is activated,a video signal system corresponding to a previously set position numberis read (step ST9), and a video signal system indicated by a positionnumber pointer 110 is loaded in a first register 130 (step ST10).

Then, a tuning data memory 62 in the memory 6 is activated, a videosignal system corresponding to the station number is read, and a videosignal system indicated by a station number pointer 120 is loaded in asecond register 140, so that a comparison part 150 compares the videosignal systems which are loaded in the first and second registers 130and 140 respectively with each other and a determination part 160 makesa determination (step ST11).

When the video signal systems match with each other at the step ST11,the station number is stored in a sorting result memory 63 in the memory6 in correspondence to the position number (step ST12).

Then, the position number is incremented by one in the position numberpointer 110 (step ST13).

Then, the station number pointer 120 determines whether or not thecurrent station number reaches the upper limit (step ST14).

Also when the video signal systems mismatch with each other at the stepST11, the operation at the step ST14 is carried out.

If the current station number does not reach the upper limit at the stepST14, the station number is incremented by one in the station numberpointer 120, to carry out the operation following the step ST11 again(step ST15).

When the current station number reaches the upper limit, on the otherhand, the position number pointer 110 determines whether or not allvideo signal systems are sorted, i.e., whether or not the positionnumber reaches the upper limit (step ST16).

If a determination is made at the step ST16 that all video signalsystems are sorted, the sorting operation is ended.

If all video signal systems are not sorted, on the other hand, theposition number pointer 110 increments the position number by one, tocarry out the operation following the step ST12 again (step ST17).

The aforementioned automatic tuning apparatus A12 comprises the sortingcontrol circuit 100 and the video signal system discrimination circuit400 so that a broadcasting station of a predetermined video signalsystem is automatically set for each position number by a sortingoperation and the user may not set the video signal system incorrespondence to the position number, whereby the burden imposed on theuser can be reduced.

Thirteenth Embodiment

FIG. 39 shows the structure of an automatic tuning apparatus A13 for aVTR according to a thirteenth embodiment of the present invention.Referring to FIG. 39, structural parts identical to those of theautomatic tuning apparatus A12 described with reference to FIG. 36 aredenoted by the same reference numerals, to omit redundant description.

Referring to FIG. 39, a user input control circuit 200 for the user formaking setting is connected to a memory 6, and a system controller 7E isformed by a tuning control circuit 5, the memory 6, a sorting controlcircuit 100 and the user input control circuit 200. A key input unit 300for the user for inputting setting is connected to the user inputcontrol circuit 200. The structures of the user input control circuit200 and the key input unit 300 have been described with reference to theeleventh embodiment, and hence redundant description is omitted.Further. the sorting control circuit 100 and the user input controlcircuit 200 employ the video signal system in place of broadcastingstation information (station ID), and hence "station ID" in theautomatic tuning apparatus A11 described with reference to the eleventhembodiment of the present invention is re-read as "video signal system".

With reference to flow charts shown in FIGS. 40 and 41, the operation ofthe automatic tuning apparatus A13 is now described. First, the userinputs a video signal system through the key input unit 300 incorrespondence to a position number, and sets the sorting order (stepST1).

Then, when a command for auto tuning is received, the system controller7E sets the memory address of the memory 6 at a station number "0" (stepST2).

Then, a tuning control signal S3 is transmitted to a tuner circuit 2A,to control the same in a direction for increasing the tuning frequencyby a constant amount (step ST3). At this time, an AFT signal S4 which isoutputted from an AFT detection circuit 4 and a SYNC signal S2indicating presence/absence of a signal separated by a video signalprocessing circuit 3 are inputted in the tuning control circuit 5 fordetecting presence/absence of a broadcasting station transmitting asignal of the frequency, to make a discrimination (step ST4).

When both of the AFT signal S4 and the SYNC signal S2 are supplied atthis point of time, the tuning control circuit 5 determines that thesignal from the broadcasting station can be received, and the currenttuning data is stored in the address of the station number "0" in thememory 6 (step ST5).

At the same time, the discrimination result of the video signal systemis obtained from the video signal system discrimination circuit 400(step ST6).

The discrimination result of the video signal system is stored in theaddress of the station number "0" in the memory 6, similarly to datarelated to the frequency (step ST7).

Then, the address of the memory 6 is incremented by one to a stationnumber "1" in order to store next tuning data, for entering a nexttuning operation (step ST8).

If both of the AFT signal S4 and the SYNC signal S2 are not supplied atthe step ST4, on the other hand, a discrimination is made as to whetheror not the current frequency reaches the upper limit of the tuningfrequency, i.e., whether or not the tuning is ended (step ST8). If thecurrent frequency does not reach the upper limit of the tuningfrequency, the operation at the step ST2 is carried out again and theoperations through the steps ST3 to ST8 are repeated until the upperlimit of the tuning frequency is reached.

If the upper limit of the tuning frequency is reached at the step ST9,the process enters a sorting operation of the sorting control circuit100. First, a sorting reference memory 61 in the memory 6 is activated,a video signal system corresponding to a previously set position numberis read (step ST10), and a video signal system indicated by a positionnumber pointer 110 is loaded in a first register 130 (step ST11).

Then, a tuning data memory 62 in the memory 6 is activated, a videosignal system corresponding to the station number is read, and a videosignal system indicated by a station number pointer 120 is loaded in asecond register 140, so that a comparison part 150 compares the videosignal systems which are loaded in the first and second registers 130and 140 respectively with each other and a determination part 160 makesa determination (step ST12).

When the video signal systems match with each other at the step ST12,the station number is stored in a sorting result memory 63 in the memory6 in correspondence to the position number (step ST13).

Then, the position number is incremented by one in the position numberpointer 110 (step ST14).

Then, the station number pointer 120 determines whether or not thecurrent station number reaches the upper limit (step ST15).

Also when the video signal systems mismatch with each other at the stepST12, the operation at the step ST15 is carried out.

If the current station number does not reach the upper limit at the stepST15, the station number is incremented by one in the station numberpointer 120, to carry out the operation following the step ST12 again(step ST16).

When the current station number reaches the upper limit, on the otherhand, the position number pointer 110 determines whether or not allvideo signal systems are sorted, i.e., whether or not the positionnumber reaches the upper limit (step ST17).

If a determination is made at the step ST17 that all video signalsystems are sorted, the sorting operation is ended.

If all video signal systems are not sorted, on the other hand, theposition number pointer 110 increments the position number by one, tocarry out the operation following the step ST11 again (step ST18).

The aforementioned automatic tuning apparatus A13 comprises the userinput control circuit 200 in addition to the sorting control circuit 100and the video signal system discrimination circuit 400, whereby thebroadcasting stations desired by the user are automatically set at therespective position numbers by sorting the broadcasting stations alongthe sorting order set by the user. Although a burden is imposed on theuser in the point that he must set the position numbers and the videosignal systems, a broadcasting station of a video signal system which isresponsive to the user's necessity can be set in an area where variousvideo signal systems are mixed.

Fourteenth Embodiment

FIG. 42 shows the structure of an automatic tuning apparatus A14 for aVTR according to a fourteenth embodiment of the present invention.Referring to FIG. 42, structural parts identical to those of theautomatic tuning apparatus A10 described with reference to FIG. 28 aredenoted by the same reference numerals, to omit redundant description.In the automatic tuning apparatus A14, a sound signal systemdiscrimination circuit 500 which is connected to a tuner circuit 2A isprovided in place of the text data decoder circuit 10 of the automatictuning apparatus A10 shown in FIG. 28.

The sound signal system discrimination circuit 500 is formed by soundsignal processing means which comprises the sound processor 60 of theautomatic tuning apparatus A8 described with reference to FIG. 22, orthe sound demodulation circuit 70, the VCO 80 and the sound detectioncircuit 90 of the automatic tuning apparatus A9 described with referenceto Fin,. 25. Redundant description is omitted since the details thereofhave already been explained, and the output of the sound signal systemdiscrimination circuit 500 is called "discrimination result of the soundsystem" in the following description. Further, a sorting control circuit100 employs the sound system in place of broadcasting stationinformation (station ID), and hence "station ID" in the automatic tuningapparatus A10 described with reference to the tenth embodiment of thepresent invention is re-read as "sound system".

With reference to flow charts shown in FIGS. 43 and 44, the operation ofthe automatic tuning apparatus A14 is now described. When a command forauto tuning is received from the user, a system controller 7D sets thememory address of a memory 6 at a station number "0" (step ST1).

Then, a tuning control signal S3 is transmitted to the tuner circuit 2A,to control the same in a direction for increasing the tuning frequencyby a constant amount (step ST2). At this time, an AFT signal S4 which isoutputted from an AFT detection circuit 4 and a SYNC signal S2indicating presence/absence of a signal separated by a video signalprocessing circuit 3 are inputted in a tuning control circuit 5 fordetecting presence/absence of a broadcasting station transmitting asignal of the frequency, to make a discrimination (step ST3).

When both of the AFT signal S4 and the SYNC signal S2 are supplied atthis point of time, the tuning control circuit 5 determines that thesignal from the broadcasting station can be received, and the currenttuning data is stored in the address of the station number "0" in thememory 6 (step ST4).

At the same time, the discrimination result of the sound system isobtained from the sound signal system discrimination circuit 500 (stepST5).

The discrimination result of the sound system is stored in the addressof the station number "0" in the memory 6, similarly to data related tothe frequency (step ST6).

Then, the address of the memory 6 is incremented by one to a stationnumber "1" in order to store next tuning data, for entering a nexttuning operation (step ST7).

If both of the AFT signal S4 and the SYNC signal S2 are not supplied atthe step ST3, on the other hand, a discrimination is made as to whetheror not the current frequency reaches the upper limit of the tuningfrequency, i.e., whether or not the tuning is ended (step ST8). If thecurrent frequency does not reach the upper limit of the tuningfrequency, the operation at the step ST2 is carried out again and theoperations through the steps ST2 to ST7 are repeated until the upperlimit of the tuning frequency is reached.

If the upper limit of the tuning frequency is reached at the step ST8,on the other hand, the process enters a sorting operation of the sortingcontrol circuit 100. First, a sorting reference memory 61 in the memory6 is activated, a sound system corresponding to a previously setposition number is read (step ST9), and a sound system indicated by aposition number pointer 110 is loaded in a first register 130 (stepST10).

Then, a tuning data memory 62 in the memory 6 is activated, a soundsystem corresponding to the station number is read, and a sound systemindicated by a station number pointer 120 is loaded in a second register140, so that a comparison part 150 compares the sound systems which areloaded in the first and second registers 130 and 140 respectively witheach other and a determination part 160 makes a determination (stepST11).

When the sound systems match with each other at the step ST11, thestation number is stored in a sorting result memory 63 in the memory 6in correspondence to the position number (step ST12).

Then, the position number is incremented by one in the position numberpointer 110 (step ST13).

Then, the station number pointer 120 determines whether or not thecurrent station number reaches the upper limit (step ST14).

Also when the sound systems mismatch with each other at the step ST11,the operation at the step ST14 is carried out.

If the current station number does not reach the upper limit at the stepST14. the station number is incremented by one in the station numberpointer 120, to carry out the operation following the step ST11 again(step ST15).

When the current station number reaches the upper limit, on the otherhand, the position number pointer 110 determines whether or not allsound systems are sorted, i.e., whether or not the position numberreaches the upper limit (step ST16).

If a determination is made at the step ST16 that all sound systems aresorted, the sorting operation is ended.

If all sound systems are not sorted, on the other hand, the positionnumber pointer 110 increments the position number by one, to carry outthe operation following the step ST10 again (step ST17).

The aforementioned automatic tuning apparatus A14 comprises the sortingcontrol circuit 100 and the sound signal system discrimination circuit500 so that a broadcasting station of a predetermined sound system isautomatically set for each position number by a sorting operation. Whenbroadcasting stations of different sound systems of other countries aremixed around the border or the like, a broadcasting station (e.g., abroadcasting station of the user's country) which is necessary for theuser can be automatically received.

Fifteenth Embodiment

FIG. 45 shows the structure of an automatic tuning apparatus A15 for aVTR according to a fifteenth embodiment of the present invention.Referring to FIG. 45, structural parts identical to those of theautomatic tuning apparatus A14 described with reference to FIG. 42 aredenoted by the same reference numerals, to omit redundant description.

Referring to FIG. 45, a user input control circuit 200 for the user formaking setting is connected to a memory 6, and a system controller 7E isformed by a tuning control circuit 5, the memory 6, a sorting controlcircuit 100 and the user input control circuit 200. A key input unit 300for the user for inputting setting is connected to the user inputcontrol circuit 200. The structures of the user input control circuit200 and the key input unit 300 have been described with reference to theeleventh embodiment, and hence redundant description is omitted.Further, the sorting control circuit 100 and the user input controlcircuit 200 employ the sound system in place of broadcasting stationinformation (station ID), and hence "station ID" in the automatic tuningapparatus A11 described with reference to the eleventh embodiment of thepresent invention is re-read as "'sound system".

With reference to flow charts shown in FIGS. 46 and 47, the operation ofthe automatic tuning apparatus A15 is now described. First, the userinputs a sound system through the key input unit 300 in correspondenceto the position number, and sets the sorting order (step ST1).

Then, when a command for auto tuning is received, the system controller7E sets the memory address of the memory 6 at a station number "0" (stepST2).

Then, a tuning control signal S3 is transmitted to a tuner circuit 2A,to control the same in a direction for increasing the tuning frequencyby a constant amount (step ST3). At this time, an AFT signal S4 which isoutputted from an AFT detection circuit 4 and a SYNC signal S2indicating presence/absence of a signal separated by a video signalprocessing circuit 3 are inputted in the tuning control circuit 5 fordetecting presence/absence of a broadcasting station transmitting asignal of the frequency, to make a discrimination (step ST4).

When both of the AFT signal S4 and the SYNC signal S2 are supplied atthis point of time, the tuning control circuit 5 determines that thesignal from the broadcasting station can be received, and the currenttuning data is stored in the address of the station number "0" in thememory 6 (step ST5).

At the same time, the discrimination result of the sound system isobtained from the sound signal system discrimination circuit 500 (stepST6).

The discrimination result of the sound system is stored in the addressof the station number "0" in the memory 6 similarly to data related tothe frequency (step ST7).

Then, the address of the memory 6 is incremented by one to a stationnumber "1" in order to store next tuning data, for entering a nexttuning operation (step ST8).

If both of the AFT signal S4 and the SYNC signal S2 are not supplied atthe step ST4, on the other hand, a discrimination is made as to whetheror not the current frequency reaches the upper limit of the tuningfrequency, i.e., whether or not the tuning is ended (step ST9). If thecurrent frequency does not reach the upper limit of the tuningfrequency, the operation at the step ST3 is carried out again and theoperations through the steps ST3 to ST8 are repeated until the upperlimit of the tuning frequency is reached.

If the upper limit of the tuning frequency is reached at the step ST9,the process enters a sorting operation of the sorting control circuit100. First, a sorting reference memory 61 in the memory 6 is activated,a sound system corresponding to a previously set position number is read(step ST10), and a sound system indicated by a position number pointer110 is loaded in a first register 130 (step ST11).

Then, a tuning data memory 62 in the memory 6 is activated, a soundsystem corresponding to the station number is read, and a sound systemindicated by a station number pointer 120 is loaded in a second register140, so that a comparison part 150 compares the sound systems which areloaded in the first and second registers 130 and 140 respectively witheach other and a determination part 160 makes a determination (stepST12).

When the sound systems match with each other at the step ST12, thestation number is stored in a sorting result memory 63 in the memory 6in correspondence to the position number (step ST13).

Then, the position number is incremented by one in the position numberpointer 110 (step ST14).

Then, the station number pointer 120 determines whether or not thecurrent station number reaches the upper limit (step ST15).

Also when the sound systems mismatch with each other at the step ST12,the operation at the step ST15 is carried out.

If the current station number does not reach the upper limit at the stepST15, the station number is incremented by one in the station numberpointer 120, to carry out the operation following the step ST11 again(step ST16).

When the current station number reaches the upper limit, on the otherhand, the position number pointer 110 determines whether or not allsound systems are sorted, i.e., whether or not the position numberreaches the upper limit (step ST17).

If a determination is made at the step ST17 that all sound systems aresorted, the sorting operation is ended.

If all sound systems are not sorted, on the other hand, the positionnumber pointer 110 increments the position number by one, to carry outthe operation following the step ST11 again (step ST18).

The aforementioned automatic tuning apparatus A15 comprises the userinput control circuit 200 in addition to the sorting control circuit 100and the sound signal system discrimination circuit 500 so that abroadcasting station of a sound system desired by the user isautomatically set for each position number by carrying out a sortingoperation along the sorting order set by the user. Although a burden isimposed on the user in the point that he must set the position numbersand the sound systems, only a broadcasting station (e.g., a broadcastingstation of the user's country) which is necessary for the user can beautomatically set when broadcasting stations of different sound systemsof other countries are mixed around the border or the like.

Sixteenth Embodiment

FIG. 48 shows the structure of an automatic tuning apparatus A16 for aVTR according to a sixteenth embodiment of the present invention.Referring to FIG. 48, structural parts identical to those of theautomatic tuning apparatus A10 described with reference to FIG. 28 aredenoted by the same reference numerals, to omit redundant description.In the automatic tuning apparatus A16, a picture definitiondiscrimination circuit 600 is provided in place of the text data decodercircuit 10 of the automatic tuning apparatus A10 shown in FIG. 28.

The picture definition discrimination circuit 600, which is formedsimilarly to the picture definition detection circuit 30 of theautomatic tuning apparatus A3 described with reference to FIG. 7 as thethird embodiment, outputs picture definition data S7 which isproportionate to the noise quantity of a blanking part of a video signalS1 having no actual signal. Redundant description is omitted since thedetail of the picture definition detection circuit 30 has already beenexplained, and the output of the picture definition discriminationcircuit 600 is called "discrimination result of the degree of picturedefinition" in the following description. Further, a sorting controlcircuit 100 employs the picture definition information in place ofbroadcasting station information (station ID), and hence "station ID" inthe automatic tuning apparatus A10 described with reference to the tenthembodiment of the present invention is re-read as "degree of picturedefinition".

With reference to flow charts shown in FIGS. 49 and 50, the operation ofthe automatic tuning apparatus A16 is now described. When a command forauto tuning is received from the user, a system controller 7D sets thememory address of a memory 6 at a station number "0" (step ST1).

Then, a tuning control signal S3 is transmitted to a tuner circuit 2A,to control the same in a direction for increasing the tuning frequencyby a constant amount (step ST2). At this time, an AFT signal S4 which isoutputted from an AFT detection circuit 4 and a SYNC signal S2indicating presence/absence of a signal separated by a video signalprocessing circuit 3 are inputted in the tuning control circuit 5 fordetecting presence/absence of a broadcasting station transmitting asignal of the frequency, to make a discrimination (step ST3).

When both of the AFT signal S4 and the SYNC signal S2 are supplied atthis point of time, the tuning control circuit 5 determines that thesignal from the broadcasting station can be received, and the currenttuning data is stored in the address of the station number "0" in thememory 6 (step ST4).

At the same time, the discrimination result of the degree of picturedefinition is obtained from the picture definition discriminationcircuit 600 (step ST5).

The discrimination result of the degree of picture definition is storedin the address of the station number "0" in the memory 6, similarly todata related to the frequency (step ST6).

Then, the address of the memory 6 is incremented by one to a stationnumber "1" in order to store next tuning data, for entering a nexttuning operation (step ST7).

If both of the AFT signal S4 and the SYNC signal S2 are supplied at thestep ST3, on the other hand, a discrimination is made as to whether ornot the current frequency reaches the upper limit of the tuningfrequency, i.e., whether or not the tuning is ended (step ST8). If thecurrent frequency does not reach the upper limit of the tuningfrequency, the operation at the step ST2 is carried out again and theoperations through the steps ST2 to ST7 are repeated until the upperlimit of the tuning frequency is reached.

If the upper limit of the tuning frequency is reached at the step ST8,the process enters a sorting operation of the sorting control circuit100. First, a reference level for comparing received degrees of screendefinition of respective broadcasting stations is set. The maximumdetectable level of the degree of picture definition is set here (stepST9).

Then, a tuning data memory 62 in the memory 6 is activated, a degree ofpicture definition corresponding to the station number is read to becompared with the reference level, and a determination part 160 makes adetermination (step ST10).

When the degrees of picture definition match with each other at the stepST10, the station number is stored in a sorting result memory 63 in thememory 6 in correspondence to the position number (step ST11).

Then, the position number is incremented by one in a position numberpointer 110 (step ST12).

Then, a station number pointer 120 determines whether or not the currentstation number reaches the upper limit (step ST13).

Also when the degrees of picture definition mismatch with each other atthe step ST10, the operation at the step ST13 is carried out.

If the current station number does not reach the upper limit at the stepST13, the station number is incremented by one in the station numberpointer 120, to carry out the operation following the step ST10 again(step ST14).

When the current station number reaches the upper limit, on the otherhand, a discrimination is made as to whether or not the reference levelis the minimum detectable level of the degree of picture definition(step ST15).

If a determination is made at the step ST15 that the reference levelreaches the minimum detectable level of the degree of picturedefinition, the sorting operation is ended.

If the reference level does not reach the minimum detectable level ofthe degree of picture definition, on the other hand, the reference levelis decremented, to carry out the operation following the step ST10 again(step ST16).

The aforementioned automatic tuning apparatus A16 comprises the sortingcontrol circuit 100 and the picture definition discrimination circuit600 and carries out the sorting operation, whereby broadcasting stationsare automatically set in the respective position numbers from thathaving a higher degree of picture definition. Therefore, a broadcastingstation having higher picture definition is preferentially stored in thecase where the same broadcasting station is received at differentfrequencies or the like, whereby the user can receive excellentbroadcasting by selecting the broadcasting station in the order of theposition number.

When a plurality of broadcasting stations having the same levels ofpicture definition are received, the same are set at the positionnumbers in order of level comparison, i.e., the order of thebroadcasting frequencies.

At the step ST9, the first set reference level may alternatively set atthe minimum level.

While the sorting order is decided by the degrees of picture definitionin the aforementioned automatic tuning apparatus A16, sorting mayalternatively be carried by the amounts of noises detected by a simplenoise detector.

While the invention has been shown and described in detail, theforegoing description is in all aspects illustrative and notrestrictive. It is therefore understood that numerous modifications andvariations can be devised without departing from the scope of theinvention.

What is claimed is:
 1. An automatic tuning apparatus comprising tunermeans tune-selecting a prescribed channel from broadcast electric wavesincluding at least a video signal, video signal processing meansreceiving said video signal being outputted from said tuner means andseparating a synchronizing signal being included in said video signal,AFT detection means detecting presence/absence of a broadcasting stationby a signal received from said tuner means, tuning control meansreceiving said synchronizing signal from said video signal processingmeans and an AFT signal from said AFT detection means for controlling atuning operation of said tuner means, and memory means being connectedto said tuning control means for storing data being related to at leastthe tuning frequency of said tuner means,said automatic tuning apparatuscomprising:synchronizing signal discrimination means receiving saidsynchronizing signal from said video signal processing means andcounting the pulse number of said synchronizing signal per second fordiscriminating the video signal system of said video signal in responseto said pulse number and outputting the result of said discrimination asa synchronizing signal discrimination signal, and tuning mode switchingmeans receiving said synchronizing signal discrimination signal foroutputting a tuning mode switching signal for changing the tuning modeof said tuner means in response to said signal system of said videosignal and supplying said synchronizing signal discrimination signal tosaid tuning control means, the tuning mode of said tuner means beingautomatically changed in response to said signal system of said videosignal, said tuning mode of said tuner means being stored in said memorymeans along with said data being related to the tuning frequency throughsaid tuning control means.
 2. An automatic tuning apparatus comprisingtuner means tune-selecting a prescribed channel from broadcast electricwaves including at least a video signal, video signal processing meansreceiving said video signal being outputted from said tuner means andseparating a synchronizing signal being included in said video signal,AFT detection means detecting presence/absence of a broadcasting stationby a signal received from said tuner means, tuning control meansreceiving said synchronizing signal from said video signal processingmeans and an AFT signal from said AFT detection means for controlling atuning operation of said tuner means, and memory means being connectedto said tuning control means for storing data being related to at leastthe tuning frequency of said tuner means,said automatic tuning apparatuscomprising:color signal discrimination means receiving saidsynchronizing signal from said video signal processing means andcounting the frequency of a color burst signal being superposed on thetrailing edge of said synchronizing signal for discriminating the videosignal system of said video signal in response to said frequency andoutputting the result of said discrimination as a color signaldiscrimination signal, and tuning mode switching means receiving saidcolor signal discrimination signal for outputting a tuning modeswitching signal for switching the tuning mode of said tuner means inresponse to said signal system of said video signal and supplying saidcolor signal discrimination signal to said tuning control means, thetuning mode of said tuner means being automatically changed in responseto said signal system of said video signal, said tuning mode of saidtuner means being stored in said memory means along with said data beingrelated to the tuning frequency through said tuning control means.
 3. Anautomatic tuning apparatus comprising tuner means tune-selecting aprescribed channel from broadcast electric waves including at least avideo signal, video signal processing means receiving said video signalbeing outputted from said tuner means and separating a synchronizingsignal being included in said video signal, AFT detection meansdetecting presence/absence of a broadcasting station by a signalreceived from said tuner means, tuning control means receiving saidsynchronizing signal from said video signal processing means and an AFTsignal from said AFT detection means for controlling a tuning operationof said tuner means, and memory means being connected to said tuningcontrol means for storing data being related to at least the tuningfrequency of said tuner means,said automatic tuning apparatuscomprising:synchronizing signal discrimination means receiving saidsynchronizing signal from said video signal processing means andcounting the pulse number of said synchronizing signal per second fordiscriminating the video signal system of said video signal in responseto said pulse number and outputting the result of said discrimination asa synchronizing signal discrimination signal, and color signaldiscrimination means receiving said synchronizing signal from said videosignal processing means and counting the frequency of a color burstsignal being superposed on the trailing edge of said synchronizingsignal for discriminating the video signal system of said video signalin response to said frequency and outputting the result of saiddiscrimination as a color signal discrimination signal, tuning modeswitching means receiving said synchronizing signal discriminationsignal and said color signal discrimination signal for outputting atiming mode switching signal for switching the tuning mode of said tunermeans in response to said signal system of said video signal andsupplying said synchronizing signal discrimination signal and said colorsignal discrimination signal to said tuning control means, the tuningmode of said tuner means being automatically changed in response to saidsignal system of said video signal, said tuning mode of said tuner meansbeing stored in said memory means along with said data being related tothe tuning frequency through said tuning control means.
 4. An automatictuning apparatus comprising tuner means tune-selecting a prescribedchannel from broadcast electric waves including at least a video signal,video signal processing means receiving said video signal beingoutputted from said tuner means and separating a synchronizing signalbeing included in said video signal, AFT detection means detectingpresence/absence of a broadcasting station by a signal received fromsaid tuner means, tuning control means receiving said synchronizingsignal from said video signal processing means and an AFT signal fromsaid AFT detection means for controlling a tuning operation of saidtuner means, and memory means being connected to said tuning controlmeans for storing data being related to at least the tuning frequency ofsaid tuner means,said automatic tuning apparatus comprising:video signalsystem discrimination means receiving said synchronizing signal fromsaid video signal processing means for discriminating the video signalsystem of said video signal and supplying the result of saiddiscrimination to said memory means as video signal system information,and sorting control means automatically sorting storage contents beingstored in said memory means, including at least said data being relatedto the tuning frequency of said tuning means, in previously set order,said video signal system information being stored in said memory meansalong with said data being related to the tuning frequency through saidtuning control means, data being related to said video signal systeminformation and corresponding said tuning frequency being automaticallysorted in previously set order.
 5. The automatic tuning apparatus inaccordance with claim 4, further comprising sorting order set meansbeing connected to said memory means for arbitrarily setting sortingorder of said storage contents.
 6. The automatic tuning control unit inaccordance with claim 4, whereinsaid video signal system discriminationmeans includes:synchronizing signal discrimination means receiving saidsynchronizing signal from said video signal processing means andcounting the pulse number of said synchronizing signal per second fordiscriminating the video signal system of said video signal in responseto said pulse number, said video signal system information being asynchronizing signal discrimination signal being outputted from saidsynchronizing signal discrimination means as the result of saiddiscrimination.
 7. The automatic tuning control unit in accordance withclaim 4, whereinsaid video signal system discrimination meansincludes:color signal discrimination means receiving said synchronizingsignal from said video signal processing means and counting thefrequency of a color burst signal being superposed on the trailing edgeof said synchronizing signal for discriminating the video signal systemof said video signal in response to said frequency, said video signalsystem information being a color signal discrimination signal beingoutputted from said color signal discrimination means as the result ofsaid discrimination.
 8. The automatic tuning control unit in accordancewith claim 4, whereinsaid video signal system discrimination meansincludes:synchronizing signal discrimination means receiving saidsynchronizing signal from said video signal processing means andcounting the pulse number of said synchronizing signal per second fordiscriminating the video signal system of said video signal in responseto said pulse number, and color signal discrimination means receivingsaid synchronizing signal from said video signal processing means andcounting the frequency of a color burst signal being superposed on thetrailing edge of said synchronizing signal for discriminating the videosignal system of said video signal in response to said frequency, saidvideo signal system information being a synchronizing signaldiscrimination signal and a color signal discrimination signal beingoutputted from said synchronizing signal discrimination means and saidcolor signal discrimination means as the results of saiddiscriminations.